Hm, sounds legit but I'm not actually sure whether it was a GU or a glitch as you say. The thing I witnesses yesterday wasn't the regular glitching I see several times every week. Yesterday, the "update" occurred with my application was similar to those I had seen two times much earlier in this year, which had been confirmed by an IRCC officer as GUs.system glitch , not a GU. I cannot even log into my account now. Lol
Despite this, nothing was changed in my profile. I guess my application was just touched, nothing important took place.