Program "glitches"...what causes them???

[DR'76]

Have a '76 w/ '95 LT1/4L60e and was just cruisin' around town, when suddenly the shifting got "weird" - wouldn't go into 4th, torque converter would not go into "Locked" status, seemed to be "slipping" in forward gears (like I had a REALLY high stall), but Reverse was OK... I pulled over as soon as I could, but couldn't find an answer...No DTC's, tranny fluid level was fine (I happened to have some fluid w/ me and did "top it off", but it was probably less than an 1/8 quart), no disconnected wires that I could see, nothing dripping, etc... Since I was close to home, it did drive it home and just since I had NO ideas, I decided to re-flash the PCM w/ the same program I had in it, and all was back to normal...?!?!?! Does this make sense? Does the program get "bugs / glitches" in it? I JUST ordered Datamaster yesterday, so couldn't log it (I used my last "freebie" just a few days ago). Is there a way to avoid this? I would hate to be out in "booneyville" w/o a laptop and have this happen again. Thanks for your thoughts!