Payback of Plan Loan Offset

Terminated Client receives 2 1099's re 401k plan loan offset. One shows M-1 Qualified Loan Offset Gross and Tax are 12,165.  The other 1099 shows B-1Designated Roth Account Distribution with Gross 13,850 and Taxable 6,122 (with difference 7,728 (employee designated Roth Contributions).  If Client puts funds back in to Roth account ($18,287 via rollover designation) how is this reflected on the tax return since Vanguard will provide no documents until 2026.  Should client report 0 taxable distributions on the 1099's?  Also, must the tax return be filed no later than October 15 for this election to payback loan offset to be valid.  Thanks