I've noticed that many aftermarket vendors/distributors will try to "standardize" parts from various models. They'll use a part that "fits", but isn't built to same spec as OEM parts. The commonality saves them on inventory cost, but in the end, the customer doesn't get a part that's 100% correct. Problem increases as we get more "cheap foriegn parts" (as opposed to EXPENSIVE foriegn parts?????) Not naming names, but I've ran onto that problem with a number of parts houses.
It's not out of the realm of possibility that the ORIGINAL solenoid went bad, but repeated failures is a red flag. If you bought aftermarket, go get an OEM part. If you bought OEM, try aftermarket this time.
And, as mentioned, check rating and try for something "heavier duty".
Personally, I prefer Bosch electrical components when I can find them. JMHO on that one....