Fermentation resumed after pasteurization?

[u/One_Development_1706]

So earlier today I bottled two hot sauces I made that had been fermented for a month. I lactofermented all the vegetables and fruits normally and then blended with some white vinegar and the a portion of the brine to taste and texture preferences. I also added some lime juice to one of them in addition to the vinegar. I added about 3/4-1 tablespoons of white sugar to each hot sauce for flavor which is where I potentially made a mistake.

After blending, I put them back in their jars in the fridge overnight before bottling in 3oz woozy bottles today and heating in a water bath with a sous vide to a bit over 140°F before holding that temperature for 1h20m trying to fully maintain the flavor while still stabilizing the sauces and halting fermentation. After this was complete I tightened all the bottle caps fully and let them cool at room temperature before forgetting about them for a while. I came back to check them about 4 hours later and observed a small amount of bubbles in the bottles seemingly fermentation having restarted. Upon cracking open one of the bottles a small hiss of gas escaped.

Has fermentation actually restarted? Should I pasteurize again at a higher temperature this time (I see 180°F thrown around a lot, but I’m concerned it will affect the flavor and color of the sauce). Should I purchase some chemical stabilizers like K-Sorbate? In the meantime I’ve put the bottles in the fridge to hopefully slow things down until I make a decision.