Never seen the bar break up like that
Hi bud, ive never seen that bar disappear completely like that....i know it changes colour with signal strength etc but not ever seen it go completely like that. I have had 4 HTC's all running various versions of Anroid and different ROMS too but like i say....it sounds like a fault. You mention it has a bug that results in high drain...this confirms my suspicions(opion only)
Have you tried a full wipe/factory reset?
Samsung Galaxy S4 loaded with super smooth, powerforce v17 Omega magic