It may only be me, but after updating forge to use the latest IC2 version I crash when opening the achievement box. No crash log, only a blank light blue screen.
Everything worked fine with all the same mods installed before updating.
Nothing unusual happens outside of this.
If it helps, here are the mods I use:
-Redpower 2 pr4d
When I click on the achievement box in the menu, it'll come up for a few seconds before doing the above. It shows the IC side of the achievements AND the vanilla ones all at once, with the regular "open the inventory" and "getting wood" achievements lit up. I can gain at least the vanilla ones, I have not tried to get IC ones.