Unable to gettexture from propertyblock

I want to get the texture from a material already assigned to _rend1 and pass it to an override material via _rend2. I can do it by accessing the materials directly but have so far failed when I try to use propertyblocks. (renderers are assigned in the inspector)

Code (CSharp):

1.   MaterialPropertyBlock propBlock1 = new MaterialPropertyBlock();
2.   _rend1.GetPropertyBlock(propBlock1,0);
3.   Texture gotTexture = propBlock1.GetTexture("_BaseColorMap");
4.  
5.   MaterialPropertyBlock propBlock2 = new MaterialPropertyBlock();
6.   _rend2.GetPropertyBlock(propBlock2,0);
7.   propBlock2.SetTexture("_BaseColorMap", gotTexture);
8.   _rend2.SetPropertyBlock(propBlock2,0);
9.  

This produces an error where gotTexture is flagged as null when I use it in SetTexture() on propBlock2.
If I set a new texture on propBlock1 and then read it back, that works fine. What do I need to do to get the original texture from propBlock1?