Plan Mode, Payload & Fuel

Hi all, I'm not quite sure if I'm doing anything wrong here, but I've got a weird behavior in regards to the plan mode and after that pretty much all the custom (PMDG specific) options in the CDU. So first of here's what I'm doing:- Entering the flight plan in the RTE, DEP/ARR pages, including SID/STAR, approaches and runways (I know it's not realistic to enter the arrival information before flying, but when you fly without any weather for the initial testing and learning - why not? ;) )- then I'm activating and executing the plan in RTE- Now I'm switching to to plan mode to see if the flight plan will work like this, as far as I'm remembering from all the Boeing planes you'll go to the LEGS page on the CDU and then press STEP to switch from one waypoint to the next (correct so far?) But initially the STEP on LSK6R is somehow missing, now when I'm switching between a few CDU pages it somehow comes up, so far so good.Only problem is, after that I cannot change any PMDG options in the CDU anymore. All values for payload and fuel are just empty (however EzDok is shifting the camera when pressing the "Random" payload LSK, so I suppose it's still working, just no values displayed). By no values I mean there is actually nothing in the CDU, the screen is completely black. Same when trying to load a panel state. Now funny thing, when I'm changing to the PERF page on the CDU, the calculated GW entry is as well missing completely, the title is there but absolutely no value displayed, just empty on LSK1L. Entering a value isn't possible as well, changing the ZFW accomplishes nothing. I'm not quite sure If I'm doing something wrong here, is maybe someone of you able to reproduce this issue? Best regards to you all, and thank you PMDG for this awesome plane!