I have recently used SimBrief to create 2 flight plans out of GMAD Agidir MO to Brussels and Krakow which are both definitely east bound routes. I used the auto select for Flight levels and on both trips and was assigned FL340. East bound should be assigning odd flight levels. I edited and assigned FL350 and all good.
Someone should look at this issue as it may be systemic.
Many regions in Europe use a North-South rule, instead of the typical East-West rule.
Taking your GMAD-EPKK flight as an example, you are in North-South airspace for the first 3 hours until you reach Vienna FIR. In such airspace, northbound flights are to file even altitudes.
Normally, once you cross into Vienna FIR (over the MALUG waypoint), you would step up or down 1,000 feet to an odd altitude at that point. However, since you had disabled the stepclimbs option on your flight, SimBrief did not plan this stepdown.