So I just accidentally right-clicked a Cika log, added by the Biomes You'll Go mod with my spear and ended up stripping it. Confused I tried the log next to it as a test and I stripped it again. I then pulled out a vanilla oak log and also stripped it with the spear.

I... don't think this is intended?

lol, it is not intended, but it is currently built from an axe so that it has shield breaking potential. I am working on a way to have the shield breaking without the axe preset. Thanks for making an issue report, because this is, indeed, a bug