Basically, the linear collapse is used to simplify the circuit for certain types of simulations, but it can't be used with AC analysis.

Also, the simulator is trying to stabilize the circuit due to potential floating nodes or instability issues. in this case I guess you need to verify your circuit connections and see if all components are properly connected.

Amina Aghanim No mam, circuit connections are complete, no issues or warnings.

These seem to be warnings, not errors. You might be running multiple simulations.