MFD Consumption--Skipping 5 min interval readings after New HV Battery Install

Hi All! Does anyone know if this might be indicating something big? Today while freeway driving, I noticed that the consumption graph entirely skipped two consecutive 5 min interval readings. I bought this 2008 only about 5 months ago, and just had to have yhe HV battery replaced --dealer new (triangle of death at only 120k miles?). My repair guys also showed me there was evidence that someone had been in that battery case prior to this replacement... So, now I'm concerned about the car's history (dealer was a total squirrel too) and I'm wondering if maybe something ELSE has been causing the battery to fail --likely now more than once (?) For 2 weeks after the replacement I saw pretty great mileage but suddenly yesterday I noticed my mileage display dropped down to around 36mpg from 42+ for seemingly no good reason, and though it's inched back up above 39, I noticed today on the freeway that the consumption graph didn't register ANY mileage reading for two consecutive 5 minute intervals. Any thoughts or comments? All greatly appreciated! Thanks!!