The stock servo in the Losi Minis (Spektrum SX107 / SX108) servos are absolutely junk. First I ran mine with the stock servo saver, then upgraded to the Losi aluminum servo horn and burnt up the servo on 2 laps at the track. It is most likely the servo or the slop in the servo saver. I had the same problem.
From then, I upgraded to the eco power servo that they recommend but I burnt up that too (with the losi upgraded aluminum horn)
Then, I got with my LHS and he hooked me up with a savox micro servo. I am having problems getting the servo mounted and finding a servo horn that will fit since savox micro servos are I believe have a 21 tooth spline or something odd like that. I found that Hot Racing made one for the savox so I got that, I also trying to test fit the servo between the stock servo mounts and cheap ebay 3d printed ones. I haven't really did much since then since I need to rebuild my whole mini b too. Which I will get started on that in a few weeks to get it ready for some carpet club racing.
Getting back to the problem here, I believe its the slop in the servo saver. I seen some people on FB put a ziptie around the saver to strength it. I did it my self and it really didn't work. You could upgrade to the Losi aluminum horn but like my story I burnt up the servo.
If your looking for a whole new servo setup, I would get either a savox with the
Hot Racing servo saver, or I seen alot of mini B / T racers use the NSDRC servo with their mount / horn.
)
