"TVOL" is "Tape" volume; "SVOL" is daily short volume (sourced from FINRA), and "FTD" is fails to deliver (sourced from the SEC).
Tape volume is verified via FINRA, but on rare occasions doesn't match up. In this case, on 22 March, FINRA shows a daily volume of only 72,328 shares; daily time and sales data reveal two trades of 1,500 shares each that occurred seconds after the 1600 closing bell, which were evidently included on the tape, but not recognized by FINRA.
The salient point is that the "fails" in ABAT are sporadic, and are frequently resolved. If there was a persistent "naked" short position, fails would also be persistent. (The SEC publishes fails data roughly every two weeks. The most recent report available as of today is for 2nd half March; 1st half April should be available some time next week.)