Kevin Hmm, wondering if it's a conflict between end time of charge slot at 15:30 and start time of export at 15:30....
Yep, that's it, it's been treated as overlapping schedules by Growatt. Confirmed via Shinephone app by configuring ending charge (Battery first) at certain time and using Grid first start time that's the same.
@Kevin Server fix being rolled out now, should be available to test in the next 10-15 mins.