I decided to make a little record-factory using the heisei dream, but in my testing I noticed that the skeleton would just keep shooting, long after the creeper was dead. This is the result: https://i.imgur.com/xUP0qVv.png

181, single player, ftb infinity pack

Then never mind my solution

So a bug that can be reproduced 100% of the time and if left alone can lag the fudge out of a world is not worth fixing, yup, okay.
Vazkii refuses to fix it and there's no workaround for it in 1.7.10
Great, instead of a music disc farm I built a lag machine. At least I can mark the challenge in the Lexica Botania as completed..

This is still an issue, most of the arrows won't despawn, thus creating unnecessary lag.

Of course this is still an issue, like vazkii said, this is not worth fixing. Please stop talking about it, as the result will not change. (I come bearing a temp solution tho, place a command block with a timer with an 200 tick (10 second) interval, and make it execute "kill @e[type=Arrow]" ( my limited amount of command knowledge tells me this should(?) work))

@JRoffel Nope, the target selector arguments for @e come from 1.8.

@howtonotwin maybe the "all" selector (@A) will work? Or does that not target entities like the arrow if you give it a type parameter?

nope, entity targeting is ONLY possible 1.8 and further.

Not worth fixing.