It has been about 2.5 years since Baro has sold Primed Bane of Corrupted. According to the wiki, it was last available from him on PC on 2021-03-26. While I realize his stock rotates, something seems wrong that it hasn't appeared in over 2 years.
If I recall correctly, it used to be that he would sell all four faction mods during the same visit, so Primed Banes of Corrupted, Infested, Grineer, and Corpus would be available at the same time. That seemed to change when the Baro relay visits were synced with consoles (though it's been over 2 years for them too.)
I do wish that you would return to that system, or change your algorithms to have each item in his stock appear at least once each year.
I do realize I could get a Tennocon ticket, but $25 for one mod, or even 500p (warframe.market) for one mod seems an excessive price for a mod that doesn't even require grinding.