The title says it all. You should avoid packaging APIs with your compiled mod, it causes all kinds of problems, especially if you're bundling an outdated API!

APIs should be located in src/api/java according to the Maven style, and when you build they won't be packaged.

We even have an annotation from Forge to help out if it isn't a hard dependency, @Optional.Interface

Thank you for helping me out! I have resolved this issue

No problems. Feel free to checkout MoarPeripherals... it is far from perfect, everyone has their own style, but there are some techniques I'm making use of in there that you may benefit from using.

Pro tip: Closing Issues from commits is helpful as it allows you to see the link between issues and the commits that fixed them.