When I let the jetpack deplete its energy entirely while wearing a solar helmet, I experience the fall damage bug akin to IC2 1.95b. Its as if the jetpack thinks it has no energy, yet the helmet is allowing flight still - so its only calculating total descent.
Console produced no error. Also, are the bug-fixers aware of the flashing solar helmet bug in crafting recipes? NEI bug?
Edit: So I've managed to fix the bug. While on a server, the solar helmet will always think it's daytime client-side, and will only ever consider it night when weather is on. This is obviously buggy! And, it won't happen in singleplayer - go figure? I can't say whether this fix works in 1.103 because it's so buggy I refuse to use it. This bug also exists in 1.103, by the way.
For the IC2 coding gurus:
I added a check for !var1.worldObj.isDaytime() to the onTick class in ic2/common/ItemArmorSolarHelmet since onDaytime() appears to be totally borked client-side in SMP. Yeah, it seems to be saying: "if its NOT daytime, charge your chest armor." But, it worked and I'm happy.
Hope it helps!