Why does the VPI motor thump

My Classic had no problem with ASR integrated amp. When I swithced to Lamm, I had the thump problem. My local VPI dealer
just came over and change the capacitor for me. If I remember properly, it was just a capacitor with a little clip on thing, took all of 10 second to change it but it has to be done from the underside of the turntable. No more problem for a long time now.

I asked my local VPI dealer once why VPI does not install the bigger cap right from the beginning so we can avoid this problem. I was told that the big cap does not totally prevent the problem either as some systems will have the same problem with bigger cap rather than the smaller cap ( I don't know if this is really true but it is what I was told anyhow) so it seems like there are 2 versions of the cap and VPI installed the one that should work with the majority of the system (80% per VPI)as standard. If this is the case, I don't see that it is any different than certain preamp that needs to be turned on before power amp otherwise you can get a big thump as well if you turn it on after turning on power amp and I would not think that that preamp is crap either!