Definitely something going on with the source linker. Others have reported similar problems. Have you tried clearing temporary files/cache, resetting FamilySearch cookies, switching browsers or restarting your computer? Please do some computer housekeeping chores and then let us know if the source linker behaves better.
For your reference, in case you need it:
Good luck. Hopefully things will work better quickly.
Thank you. Clearing the cache seemed to take care of the problem.
That's great. Glad things worked out.