adjustTimeStep/writeInterval conflict

I'm running a very simple test case using interPhaseChangeFoam and found out that monitors written every writeInterval based on adjustableRunTime conflict with the adjustTimeStep option.

For example, if monitors are not used and a max Courant of 0.5 is specified, the solver runs fine with a time step size of the order of 1e-4 after an initial transient regime from the specified time step size of 1e-6.

If monitors are activated with a writeInterval of 1e-3, the case runs initially fine but then the time step size drops suddenly to 1e-28.

## Reattaching the author to the issue ticket: @Ricky-11 ##