Can't mark candidates with `helm-projectile-ag`

[ZedThree]

Using helm-projectile-20250814.1150, when I search a project with helm-projectile-ag, I get "[Marking not allowed with this source]". I can mark candidates with helm-projectile-grep and with helm-ag.

I've checked this behaviour is present with emacs -Q and loading just helm, projectile, and helm-projectile. Is this the intended behaviour? I'm sure that it used to work previously.

(Thanks for this fantastic project btw!)