Battery dead. Can't Pop Start - gear "not engaged" mystery

Duh - I left the key in the ignition, and ON so naturally the battery drained.  Not big surprise.  What happened next is a total mystery.  I assumed that I could just put the bike in gear, and pop start it.  However, when I put the bike into first (or any other gear) the gears did not "engage".  In other words, in first gear, with clutch OUT (not engaged) I was able to push the bike as if it were in neutral.  I have never seen this happen.  Since it was not engaged, I could not push start it.

I connected my XP1 charger today and the bike started right up.  The first time I put it into first, the same thing happened - the gear did not engage.  I tried second, that worked.  I rode around for a few minutes and then everything worked fine.  Rode for a while, battery charged, life is good.  But I am still very confused about when happened.


Any helpful comments would be appreciated.

Buck

If the battery is completely dead then the fuel pump will not prime so bump-starting the bike will not work.

As far as I know there is no connection between the electrical system and the gear selector; the only thing I can offer is that for a gear to engage there has to be some stress to the mechanism, so if the motor is not spinning, you may have to rotate the rear wheel a bit for a gear selection to stick. Not being able to engage first gear but successfully engaging second is something that does happen, not very frequently, but not unheard of either.

Makes Sense..

Thank you!