I don't know if this is a feature, but suddenly I can't put copper from mekanism in a drawer that has Thermal Foundation copper or vice versa. I am using 5.2.9. I'll update to 5.3.0 to see if it has been changed but I don't see an issue about it so I'll open one.

I'm having a similar issue - i have the Conversion Upgrade installed, but i'm unable to insert Menril Logs into a drawer of Oak Logs, despite them being oredict'd to 'any log'.

Random thought: do you have the conversion upgrade installed?