[Windows] Crash caused by Animator::UpdateAvatars

Hi,

We are facing a random crash in a build made with Unity 2019.2.16f1.
With WinDbg, running !analyze -v after setting .sympath+ SRV*c:\symbols-cache*http://symbolserver.unity3d.com revealed this:

Code (CSharp):

1. ************* Path validation summary **************
2. Response                         Time (ms)     Location
3. Deferred                                       srv*
4. Deferred                                       SRV*c:\symbols-cache*http://symbolserver.unity3d.com/
5. 0:000> !analyze -v
6. *******************************************************************************
7. *                                                                             *
8. *                        Exception Analysis                                   *
9. *                                                                             *
10. *******************************************************************************
11.  
12. *** WARNING: Unable to verify timestamp for T******.exe
13. *** WARNING: Unable to verify checksum for mono-2.0-bdwgc.dll
14. *** WARNING: Unable to verify timestamp for nvwgf2umx.dll
15.  
16. KEY_VALUES_STRING: 1
17.  
18.     Key  : AV.Dereference
19.     Value: NullClassPtr
20.  
21.     Key  : AV.Fault
22.     Value: Write
23.  
24.     Key  : Analysis.CPU.mSec
25.     Value: 7593
26.  
27.     Key  : Analysis.DebugAnalysisManager
28.     Value: Create
29.  
30.     Key  : Analysis.Elapsed.mSec
31.     Value: 12858
32.  
33.     Key  : Analysis.Init.CPU.mSec
34.     Value: 514
35.  
36.     Key  : Analysis.Init.Elapsed.mSec
37.     Value: 56411
38.  
39.     Key  : Analysis.Memory.CommitPeak.Mb
40.     Value: 322
41.  
42.     Key  : Timeline.Process.Start.DeltaSec
43.     Value: 2123
44.  
45.     Key  : WER.OS.Branch
46.     Value: vb_release
47.  
48.     Key  : WER.OS.Timestamp
49.     Value: 2019-12-06T14:06:00Z
50.  
51.     Key  : WER.OS.Version
52.     Value: 10.0.19041.1
53.  
54.     Key  : WER.Process.Version
55.     Value: 2019.2.16.35214
56.  
57.  
58. CONTEXT:  (.ecxr)
59. rax=0000000000000000 rbx=0000007eda1befe0 rcx=0000000000000001
60. rdx=0000022ca777d760 rsi=0000000000000001 rdi=0000000000000000
61. rip=00007ff9c5e90fce rsp=0000007eda1bed40 rbp=0000007eda1bee40
62. r8=0000022d0c46f800  r9=0000007eda1bec88 r10=0000000000000000
63. r11=0000007eda1beb80 r12=0000000000000000 r13=0000022ca6dfd278
64. r14=000000000000006e r15=0000000000000001
65. iopl=0         nv up ei pl nz na po cy
66. cs=0033  ss=002b  ds=002b  es=002b  fs=0053  gs=002b             efl=00010207
67. UnityPlayer!Animator::UpdateAvatars+0x89e:
68. 00007ff9`c5e90fce c6405201        mov     byte ptr [rax+52h],1 ds:00000000`00000052=??
69. Resetting default scope
70.  
71. EXCEPTION_RECORD:  (.exr -1)
72. ExceptionAddress: 00007ff9c5e90fce (UnityPlayer!Animator::UpdateAvatars+0x000000000000089e)
73.    ExceptionCode: c0000005 (Access violation)
74.   ExceptionFlags: 00000000
75. NumberParameters: 2
76.    Parameter[0]: 0000000000000001
77.    Parameter[1]: 0000000000000052
78. Attempt to write to address 0000000000000052
79.  
80. PROCESS_NAME:  T************.exe
81.  
82. WRITE_ADDRESS:  0000000000000052
83.  
84. ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at 0x%p referenced memory at 0x%p. The memory could not be %s.
85.  
86. EXCEPTION_CODE_STR:  c0000005
87.  
88. EXCEPTION_PARAMETER1:  0000000000000001
89.  
90. EXCEPTION_PARAMETER2:  0000000000000052
91.  
92. STACK_TEXT:
93. 0000007e`da1bed40 00007ff9`c6626573     : 00000000`0000006e 00000000`00000000 00000000`00000000 00000000`00000000 : UnityPlayer!Animator::UpdateAvatars+0x89e
94. 0000007e`da1bf080 00007ff9`c6528977     : 0000022c`b4d62880 00000000`00000000 0000022c`b4d628e8 0000022c`00000000 : UnityPlayer!DirectorManager::ExecuteStage+0x113
95. 0000007e`da1bf0c0 00007ff9`c6528a19     : 00000000`ff515700 00007ff9`f6f5eb96 00000000`00000001 0000022c`b4d62748 : UnityPlayer!ExecutePlayerLoop+0x57
96. 0000007e`da1bf270 00007ff9`c652aa12     : 00000000`0000097c 00000000`0000000a 00000000`00000000 00000000`0000097c : UnityPlayer!ExecutePlayerLoop+0xf9
97. 0000007e`da1bf420 00007ff9`c62f3155     : 00000000`0000097c 00000000`00000000 00000000`00000000 00000000`0000000a : UnityPlayer!PlayerLoop+0x92
98. 0000007e`da1bf4a0 00007ff9`c62f1bca     : 00000000`0000097c 0000007e`da1bf640 00000000`00000000 00000000`00000000 : UnityPlayer!PerformMainLoop+0x1c5
99. 0000007e`da1bf4d0 00007ff9`c62f5c01     : 00000000`00000001 00000000`00000000 0000007e`da1bf640 00000000`00000000 : UnityPlayer!MainMessageLoop+0xda
100. 0000007e`da1bf540 00007ff9`c62f954b     : 00000000`0000000a 00000000`00000000 00000000`00000000 00007ff7`e34eb278 : UnityPlayer!UnityMainImpl+0xce1
101. 0000007e`da1cf8d0 00007ff7`e34e11f2     : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : UnityPlayer!UnityMain+0xb
102. 0000007e`da1cf900 00000000`00000000     : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : T**********!__scrt_common_main_seh+0x106
103.  
104.  
105. FAULTING_SOURCE_LINE:  c:\buildslave\unity\build\modules\animation\animator.cpp
106.  
107. FAULTING_SOURCE_FILE:  c:\buildslave\unity\build\modules\animation\animator.cpp
108.  
109. FAULTING_SOURCE_LINE_NUMBER:  1230
110.  
111. FAULTING_SOURCE_CODE:
112. No source found for 'c:\buildslave\unity\build\modules\animation\animator.cpp'
113.  
114.  
115. SYMBOL_NAME:  UnityPlayer!Animator::UpdateAvatars+89e
116.  
117. MODULE_NAME: UnityPlayer
118.  
119. IMAGE_NAME:  UnityPlayer.dll
120.  
121. STACK_COMMAND:  ~0s ; .ecxr ; kb
122.  
123. FAILURE_BUCKET_ID:  NULL_CLASS_PTR_WRITE_c0000005_UnityPlayer.dll!Animator::UpdateAvatars
124.  
125. OS_VERSION:  10.0.19041.1
126.  
127. BUILDLAB_STR:  vb_release
128.  
129. OSPLATFORM_TYPE:  x64
130.  
131. OSNAME:  Windows 10
132.  
133. IMAGE_VERSION:  2019.2.16.35214
134.  
135. FAILURE_ID_HASH:  {e64e4571-00a2-1996-ee15-5e7807ea6cf9}
136.  
137. Followup:     MachineOwner
138. ---------

What could be the cause of this crash?
Attached the crash.dmp.