The Hasselblad 500 series has a long history of problems with the film magazines malfunctioning; overlapping frames are a huge, well-known problem issue with Hasselblads of the 500C vintage; many 500C's,made before the C/M switch, are fairly old now, and the back you have no doubt needs servicing. The back issues and the shutter cocking/lens mounting issues earned the camera the nickname Hassle-blad among a certain segment that did not deify the camera. It's like any complicated, sophisticated, intricate mechanical device from the days of yore--it demands periodic tune-ups and regular maintaining.
A Hasselblad 500C might be made in 1957 or 1958--so it could be 50 years old,or older.
Check this thread from 2001
HASSELBLAD: Overlap frames with A-12 Magazine. - Photo.net Medium Format Forum
That's a bit like saying Chevy (or insert your own favorite brand here) has a known problem with engines blowing up if you never change the oil or check to see if it has any.
Precision photographic equipment requires regular service, whether it's Japanese, German, Swedish or American. Without regular service, it's a crap shoot whether it will work reliably or non (much like a car) I have used both RB67 and Hasselblads for well over two decades and can count the number of times that I had a failure that wasn't due to lack of maintenance on one hand. (exactly once, and it was an inexpensive repair) I know that in this day and age of disposable everything we assume that everything should work without any service, but it's just not so.
Even my Sinars need a tune up every few years.