Swashbuckler Finesse bonuses similar to Weapon Finesse doubling Penalties.
I've tried to make an "unchained rogue" (the unchained manual) that is also a "swashbuckler" with the "inspired blade" class (advanced class guide).
Aside from a minor weird thing about 20 arrows and the stack of arrows "arrows (20)" being obviously different. (but personally i'm not going to file an issue for that)
The main problem i see is that since both classes grant the weapon finesse feat.... it gets applied twice.
As you can clearly see in the original version i had +16 with the rapier to hit bonus, but by raising the strength by 3 points...
(i redistributed the points around so that the 4rth level increase went to dexterity instead of strength so i could actually wear the basic equipment and also carry little things like water, rations a backpack and other stuff like that, which... you know... for a roleplaying game... might be needed)
...i ended up having less to hit bonus.
i thought originally that i had messed up making the character, but the remake actually showed me that finesse is applied twice since strength got subtracted twice.
attached you will find pdfs and pcgs for looking it up wherever you are.
Microsoft Windows [Version 10.0.17763.195]
java version "11.0.1" 2018-10-16 LTS
Java(TM) SE Runtime Environment 18.9 (build 11.0.1+13-LTS)
Java HotSpot(TM) 64-Bit Server VM 18.9 (build 11.0.1+13-LTS, mixed mode)
why, yes, i do like building and testing weird stuff, but it’s not exactly an illegal build, since nowhere is written that i can’t mix swashbuckler and rogues. And since you rewrote the subject it seems you’ve found the actual problem. 😅
Okay, I’m becoming of the opinion here you like building crazy PCs that really shouldn’t be legal. Swashbuckler mixes Rogue, and per unchained rules, you cannot play a normal rogue and unchained rogue. By taking swashbuckler you are essentially building an unchained rogue and regular rogue ergo an illegal build.
Well, fact #1 - Weapon Finesse feat cannot be applied twice Fact #2 - it’s typed so the value would never stack. What is likely happening here is a class feature is granting a Weapon Finesse effect and not the feat as it should.