Thank you for posting the picture of the film strip, very helpful. Post 37, 38, and 40 are the most likely.
Now, open the camera back and inspect the take up sprockets. If the sprocket does not turn freely then use the advance lever to turn the take up. Check for any deformation of the sprockets.
Next hold your thumb against the center of the sprocket applying some pressure and advance the film lever as if advancing to the next frame, trip the shutter and repeat 3 or 4 times.
Does the sprocket turn with the advance lever without slipping. Increasing the pressure on the sprocket should make the advance lever harder to move.
Damaged/deformed sprocket(s) or slippage is a problem with the advance system.
I have a Pentax SP1000 at hand, the sprocket turns freely until the advance is operated 1 time then its locked to the film advance movement. Your camera should operate similar.