If the movement of the money from one traditional IRA to another was done by trustee-to-trustee transfer where the funds were never made payable to you personally but were instead paid directly from one IRA to the other (apparently the case since this transaction is not reflected on any Form 1099-R), the transfer is not reportable. A trustee-to-trustee transfer of one traditional IRA to another is neither a distribution nor a rollover.
The bigger question is whether or not the corrective distribution from the 401(k) was done properly since the rollover of your entire traditional IRA balance to the 401(k) apparently resulted in the impermissible rollover to the 401(k) of your basis in nondeductible traditional IRA contributions.
