Shouldn't those two be separate bugs? This one is about the fist charging as qucikly as the tools, while the other is the opposite.
Oops. I meant that the charge meter doesn't fill up correctly. So the attack speed is 4(I think non-weapons has 4?) for the tools. Sorry for being unclear.
I haven't played since the last two snapshots or so, but I tried reproducing it in 15w45a by going in and out of the nether and didn't find anything. I also tried doing the same thing in 15w41b, and the charge meter got more messed up than I remember. It's kind of hard to explain because it seemed to happen at random times.
Since I can't find the bug in 15w45a I would assume it's been fixed. I only tested this in survival mode.