I've read about loops that a PCB designer should avoid them "mostly about ground loops" but i think I've read also about power.
Trace loops are an excellent way to introduce noise to your lines. Either it is from a ground or a "positive" trace, magnetic flux that passes through the loop will induct a voltage to the resistance of the copper trace, which eventually will add up to your "normal voltage". Such magnetic fluxes can be due to power grid (50 or 60 Hz), low-end SMPS, rf signals, etc.
An excellent source for information about pcb design is analog's Linear Circuit Design Handbook (which is free to download) and from which is the following Figure
The traces you have pointed out are indeed loops. I hardly believe that they will create any notable noise, since they are small, but it is always a good practice to avoid them.
Consider just a sensor feeding a voltage to an ADC Analog Digital Converter. The ADC takes charges from the sensor, and performs the digitization. Those charges --- electrons ---- may remain inside the ADC for binary-search conversion from charges into digital-decisions, but identical charges must be returned to the Sensor.
That return-path is called Ground. Any voltage in the Ground-path causes a measurement error.
The resistance of a square of copper foil ---- if the standard thickness of 1.4 mils or 35 microns --- is 0.000500 ohms (500 microOhms) measured across opposite edges. For any size square.
Draw out the return path of your signal charges, and also determine what OTHER charges will share that return path. Why? because charges explore ALL POSSIBLE return paths, proportional to conductance.
It may be complaining because of the layer transitions. Layer transitions can be nasty for higher speed signals and analog as well. If you can, especially if they're sensitive signals, try to route them on the same layer coupled with a ground. Your board looks like its' already very tight so there may not much you can do in that department.