I have this problem too that from time to time E3372 will stop working and won't reconnect again unless I power cycle my mikrotik device. The reason for this is that mikrotik device is unable to supply enough current to the stick hence it will hang. E3372 will require up to 700ma on the USB port however maximum current the mikrotik device can provide is 500ma. The solution is using a powered USB hub. I am using a D-Link 4 port USB Hub (DUB-H4) with a power adapter and it fixed all my problems.
so, the simple flow like this ?
Modem E3372 <--> D-Link 4 Port USB Hub (no powered adapter) --> Router Board.
or like this
Modem E3372 <--> D-Link 4 Port USB Hub (with powered adapter) <--> Router Board.