Yes, I’d still say it’s most likely your ec/tds and pH. In bloom, we want that pH to be about 6.7-6.8.
I still recommend a flush at about 6.6 followed immediately by a light bloom feed at about pH 6.8.
I don’t topdress, myself, but some lime with the non blooming girls would help with pH. The plants that are firmly into bloom won’t get as much benefit from the lime, since the lime is a slow release element.