Yes, event maps all scale to your commander's level. It isn't as bad as it used to be since the commander levels at the speed of a 4* now instead of a 3*, but this is what we've dubbed the 'commander level gap.' It will continue to get harder as you go up because your commander's level will outpace the level of your 5* tanks. The eventual good news is that once your commander hits 50 you will begin to close the gap. We all had to go through it.