Aliquot Method Not Working?

Has anyone else had issues with the aliquot method? I could not get the bulk fermentation right for several loaves, so I was excited to hear about the “fool proof” aliquot method.

My recipe is 100g starter, 325g water, 500g bread flour and 10g salt. My dough temperature right before first stretch and fold was 79.4 degrees. My house is 78 degrees. I temped several more times to make sure my dough didn’t fall… it stayed pretty consistent. I use a plastic shower cap to cover my dough.

I put in the small sample into a 2oz plastic cup with lid on right before I did my first stretch and fold (one hour post mix), nestled it into the middle of the dough, and even 5 hours later (6 hours total BF), the aliquot sample hasn’t risen. Few small bubbles at the bottom, but nothing else beyond that.

After four S&Fs/few slap downs to build strength every 30 min, then letting it rest, I see changes in my main dough, like getting bigger, more bubbles on top, etc., but the sample is throwing me off. I was looking forward to using it as an indicator for when to be done with the process.

Any advice would be appreciated! 🙏🏼 whether I’m doing it wrong or if there are other indicators on how to tell when bulk is done.