Good to hear. All you're doing there is forcing any bubbles out of the system. It would be worth stripping the callipers and giving them a good clean if it comes back.
Sometimes it's worth taking the calipers off, pushing the pistons right back and jamming them back so they can't move, then tie the lever back as hard as possible; top the reservoir right up, then crack one caliper nipple, and repeat the process for the other............air and sh*te fluid can get trapped behind the pistons.
I had one of those Triumphs with exactly the same problem, the discs were also slightly warped. Swapped discs for some Brembo items, new fluid, pads, yadda, yadda - result? Perfect, minimal movement of lever, good bite, happiness! After a few rides - spongy lever movement, slightly warped discs! There's something fundamentally wrong there somewhere. Solution? Sold the camel!
