500e brakes tend to eventually start to grab a bit when switching from regen to mechanical braking at around 6mph but there's an easy fix:
On AlfaOBD ($49 version), under ABS>Renenerative Brake Controller>Active diagnostics, select procedure to start (RBC Sensor Calibration). THAT'S IT!!!
All you need is a Bluetooth OBD tool such as ELM327 KONNWEI KW902 for under $20 on eBay, & AlfaOBD app for $49 on GooglePlayStore (works on Android or laptop, but not iPhone)
P.S. ALL credit for this goes to forum members other than me. All I did was compile it with a catchy title.