I also had the "wait for PMT issue" with my TT card after standby/resume. After many changes that were done recently (i.e. stop graphs before suspend, ConditionalAccess allowing TT to stop graph), my MP/TVE3 runs very well.
I strongly recommend everyone to test the MP 1.1.0 alpha build when it's released
I had the problem again today. Only a few channels (frequencies) worked. Uninstalling and selecting "completely remove mediaportal products" and then reinstalling did NOT fix it this time.
A few frequencies don't work at all. Using other software like dvb-viewer I can view the channels.
edit: looking in tv-server setup I noticed there were a lot of channels on de 300Mhz transponder which in reality belonged on other transponders!
edit2: I used "manual scan" to find all transponders, this is what coused the channels to have the wrong frequencies. Doing a "preferred" scan on Ziggo/Casema fixed the frequencies when updating the channels.