Hi @DaveK ,
First of all, quick answer is that you can extend timeframe for your survey. I followed your test to extend timeframe (I changed my time zone on my PC to yours before this)and I could still submit survey, which also means I was not able to reproduce your issue.
I'm using Connect 3.12.232 on Mac with AGO.
Can you share more info about your situation?If so, I have questions that might be helpful to consider:
1. Is it an issue that you can steadily reproduce?
2. If so, is client's location( where this issue was encountered) the same as -04:00 time zone?