too close to bed?

Occasionally getting first layers like this on larger prints. I’m using auto-z so the offset is calibrated each time. Currently no nozzle wiper which I think is causing the issue, where filament leaks from the nozzle and causes the calibration to reduce distance from the bed as the small bit of filament between the nozzle and the Z-endstop increases the difference. This then disappears once printing starts because the filament is gone, so the nozzle just ends up too close to the bed where calibration was inaccurate. It would be helpful if anyone could confirm this is just being too close to the bed (due to auto calibrated offset) though and not another issue.