I don't know if this is a REI issue. If it is, please let me know and I'll report it there instead.

Edit: Sorry, I forgot to include some information.
MC 1.16.2
IndRev: indrev-1.5.1-BETA.jar
The same display issue appears on the flux containers

That was my mistake, it happens for every machine that does not have a config entry (it's only visual, the machine works fine). I'll fix it for the next update, thank you for reporting.

Thanks! Love your mod. :-D

This should be fixed as of 1.6.0-BETA which you can download https://www.curseforge.com/minecraft/mc-mods/industrial-revolution/files/3043918. Thanks for the report!