As someone who as doubled our eng team in the past four months and plans on doubling it again in the next 6, here's my view:

I use the term jumpy. It is a negative signal, but not a killer signal. You'll have to make up for that with numerous other positive signals, such a extreme technical competence, culture fit, evidence of shipping, etc.

I probably wouldn't point it out on a resume or whatnot, but when asked about it, be honest. Also consider being more picky about the jobs you take. Try to stick and your next place 2-3 years or switch to contracting.