You don't say which brand of Longarm you have ...HQ..gammil...apqs ...the company could help you with the problem...I have an APQS and they are great ...I have read info on this problem...I read it happens less with the L smaller bobbins as opposed to M larger size...but not sure if it's in fact true...I have L bobbin...do not have this problem...
i also use a TOWA gage to help adjust tension for breakage...and I wind my own bobbins...I prefer them to the prewounds...