Aa long as you are within the 6 months it's as if it never happened. The only exception would be if your severance is longer than 6 months and you take a payout. In that case, your seniority stays but you have to repay any extra amount received based on when you get rehired.
I had a former teammate that played this game. I think he was displaced 3 times. Each time he took 4 months off and then applied for a new position. Each time he made it under the 6 month window. Between non-working notices and the 6 months of severance, he ended up getting paid for close to 24 months without work over a 5 year period AND he still has his full severance available to him along with PTO, etc.
Perks of working near a large hub - always jobs available.