There is a previous thread about this and has been known problem since at least Feb 24 .
https://forum.trustedhousesitters.com/t/ths-reminder-emails-sending-on-wrong-dates
It happens to us even when sit is in our home country so nothing to do with time zones .
It was reported to THS in February and I reported it again when it happened last week (1 May )
The response from member services was
“ Our tech team is aware of this issue, but there is no timeframe for when it will be fixed.”