Buzzing sound when clicking starter

Iv been using the kick starter for almost a year now because of the old issue I had where the starter relay would stick and the bike would keep cranking with the ignition off until the batter died. I replaced that battery and the issue reoccured about 6 months later and since then iv been using the kick starter. I have been thinking about the issue and thought that it might be low battery voltage that caused the relay to stick because I do a lot of short trips so iv been recharging the battery every 2 days but last night on the way to work the bike didn't start I got a buzz sound from he relay but no cranking followed by nothing happening at all when I clicked the starter button no sound.... nothing.
I then recharged the battery at work and clicked the starter and again got a buzz then another buzz then the bike turned over as normal and started.

So what the hell could be the problem? Could it be the bikes charging system isn't working? Could the battery be bad again, I checked the voltage after charging and it was 13.1 volts which settles to 12.8volts but I didn't do a load test and not sure how to.

 

Load test confirms battery is fine, so I'm guessing that the starter motor is fucked and needs replacing?

 

wire your starter motor direct to the battery for a few seconds, use a couple of independent wires to bypass all other electrics.

 

The problem is intermittent so that won't confirm anything.