Mixer stops when shifting from 10 down to 8

Classic Model # k45ssac It works fine in the lower gears. If I get to 6 too fast, it stops sometimes. If I get to 10 and shift it down to 8, it stops. It turns back on at 4. Sounds fine, speed tested in all gears.

crwdns2934089:0crwdne2934089:0 crwdns2934093:0crwdne2934093:0

crwdns2934109:0crwdne2934109:0

crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0