Save streak reset due to minimum bank balance?

I noticed today that my save streak had reset, despite me not cancelling any autosaves. I raised a live chat and was told there had been 2 automatic saves unable to process due to insufficient funds in my connected account.

These saves were not showing in my account, so I queried if recently turning overdraft savings off and setting a minimum bank balance had caused the streak to end and I was told that that would be why.

I don’t really understand the logic there, as I thought that the whole point of having the minimum amount function was to stop Chip taking your bank balance down to zero each month.

Had I left the settings as they were previously the money was available in my connected account, but I no longer want to drop a certain amount or constantly dip into the overdraft.