Polkadot recently updated to version 0.8.28. In this update, there was a change in the "apply" function. The second part of the function, called "CandidacyBond," was supposed to be 100 DOT, but it was changed to 1 DOT by mistake. This caused some accounts to only have 1 DOT unreserved instead of 100 DOT. To fix this, a proposal was made to use "Balances::force_unreserve" to correct the amounts for the two affected accounts. More information can be found in the linked issue.