Yea sounds like a restriction, and perhaps a leaking wheel valve. Pressure should equalize fairly quickly each time it cycles, if it is not, ctis will fault, same if it is too uneven at the start of a cycle, pressure equalizing causes unstable pressure and the unit faults, so it takes a few cycles to deliver a stable pressure when the controller is looking for it.
Tires will equalize faster on a single axle than from axle to axle due to line/flow friction. path of least resistance is across to the opposite tire.
Fill the system to your desired pressure, then shut down and unplug the controller. Restart and go on your way without the controller tying things together every few minutes, you can then monitor individual tire pressures with your TPMS. I think you will probably find you have one tire on the front with a steady leak/decrease, and each cycle is equalizing it with the opposite front tire...