Certainly there is no pga of blue/yellow here.

It is a situation where a flag evolves into a truce. Happens sometimes and is nothing too special.

Both players acted well here from my reading. If yellow had agreed to a 1/3-fight, that would have been fine also. With blue flagging yellow it was clear he had to finish below - so letting yellow die without action was not an option from my understanding. Receiving that help from blue yellow had the chance to accept greens flag - but green flagged blue first, so he was 3rd then.

The classic problem about transitivity of flags, an unsolved issue, but certainly no pga.

If you see pga here, you need to change your medication.