Reddit users mtb_junkie and Yewtsan have suggested that disabling Bluetooth device scanning on the phone should help in at least some circumstances.

It’s not uncommon for brand new Android releases to have flaws, and we noted in our Android 11 review that the new OS appears to be buggy on the whole. The Android Auto issues appear to be particularly acute, though, and could be problematic if you depend on your phone to get around town. You may want to wait for the Auto app update and revisions to Android 11 itself before jumping in.