[sloaken]

Being it was a well known probation period, I would say not to fight it.

IMHO - the government, especially the US government has a hard time getting rid of people who do not fit in. As such they have their probation period to make life easier.

When I worked in regular industry, we liked to hire people as contractors first and if they worked out convert them. This avoided having to layoff people who did not work out. You just claim the need for their contract work went away.

DO you want to stay where they do not want you? Be active in finding a new job. Worked your hardest on delaying your departure, until you line up a new position.