so, there is one spur fix that is now consistently working for me.
among rhe solutions, i was looking for one that would be easy to apply.
first, the distortion in the 45 mhz amp is creating harmonic distortion. so a 0.3uh in series with a 10 pf is used across TP13 (output of the 45 MHz IF amp going to the front end mixer). 8 turns on T30-6 gives you 300nh.
second, there is a cross talk inside the Si5351 where the 12 mhz from the bfo leaks into the local oscillator. A 5uh in series with a 47 pf across C202 of the LPF will suppress it. 35 turns on T30-6 gives you 5uh.