nib bleed with pilot kaküno?

hello! i’ve noticed recently that my pilot kaküno f nib has been bleeding/leaking ink as i write? it’s inked with tom’s studio ink in the color midnight. the ink usually only bleeds onto the nib, but i notice now that it’s actually forming a drop and if i hesitate for too long while i write it’ll actually drop onto the paper. could my ink be too thin? i’ve been using this same ink for a little while since i had a sample, but i didn’t notice it until the last couple of days.

tia!