Contact Magnum Research for replacement parts, if you need them.
https://www.magnumresearch.com/You should be able to replace the Spring in your original Guide Rod Assembly.
I don't have a 941, so I can't tell you how it comes apart, but maybe someone else here knows.
I've heard of other Pistols with Guide Rods with Captive Springs being serviced.
I would just trim that Guide Rod Back about 1/8 of an inch and call it good. You want the Recoil Spring Guide Rod even with the lower edge of the Slide hole.
How does it shoot with the newer Recoil Spring and what Recoil Spring weight did you use?
IF the Pistol runs well with the replacement Guide Rod and Spring, you have solved the problem.