has the company(ies) adopted common paymaster status - (see link) you are supposed to be treated as an employee of only one company so excesss social security is not withheld.
this is not required but generally companies do this when they can to avoid having to pay extra social security taxes
so if this is not the case and you worked for 2 legal entities within the sme org each may withhold the max soc sec
https://www.irs.gov/government-entities/common-paymaster
you need to find out which is the case. if common paymaster, the business should refund the excess.
