EXX doesn't use startingwfc="file" correctly
Restarting from a converged EXX calculation (restart_mode='restart') can be useful to change some input parameter and keep going, without repeating the entire SCF procedure.
When restarting on top of a converged calculation, both charge density and wavefunctions are read from file. However, instead of starting directly with the EXX cycle, the code does a PBE scf loop first, which destroys all the restart data.
In general, when starting_wfc are from file (whether we are restarting or not) the EXX algorithm should skip the PBE bootstrap and go directly to EXX
Edited by Lorenzo Paulatto