There is a remote chance of botulism. https://beerandwinejournal.com/botulism/https://beerandwinejournal.com/q-a-botulism/
My question is why do you think the one split hasn’t ‘started’?
Could this be a case of a loose fermenter or airlock seal?
Remember, the lag phase is a part of the yeast life-cycle. When presented with an energy source, an adequate pitch of healthy viable yeast will ‘start’ immediately. True enough, visible signs of fermentation such as CO2 production may not be evident to us, but the process has most likely begun.
Using a TILT hydrometer, I have experienced SG drops before visible signs of fermentation are present in an airlock. This is an indication to me that everything is on track even though I can’t witness bubbles from an airlock. I’ve also seen SG drop after airlock activity is finished. Granted those drops are 1-2 points but nevertheless they still happen.
On this graph I have circled the beginning of fermentation but no bubbles escaped from the airlock at this point (or if they did they were so few and far between I didn’t see them):
Sent from my iPad using Tapatalk