You cannot chisel any material blocks (iron blocks, gold blocks, etc) as they instantly turn back into their vanilla forms.
This is probably due to the mod that automatically converts the same resources from different mods to a single form so instead of having 3 different copper ingots, you only have one.
Possible Solution
If there is a blacklist for that mod, add all the chisel blocks to them so they aren't converted
Issue
You cannot chisel any material blocks (iron blocks, gold blocks, etc) as they instantly turn back into their vanilla forms.
This is probably due to the mod that automatically converts the same resources from different mods to a single form so instead of having 3 different copper ingots, you only have one.
Possible Solution
If there is a blacklist for that mod, add all the chisel blocks to them so they aren't converted