Odd Firefox "Memory" Problem

[#1]

Not really a problem more a minor annoyance which happens only on one website. By memory I mean FF remembering a number in a box.
I use Hermes a lot so I'm often checking parcel progress. You put the parcel number in the box and check the result. Numbers fed into the box are of course remembered as usual.
But for some reason not all are. Some of the numbers beginning with eight, not all, are not remembered.
I have no idea why but I'm curious.

[#2]

Probably just a minor idiosyncratic bug outcome that will disappear in future versions.  I had my attention drawn recently  to one that didn't allow users to select the Female radio button in http://riskprediction.org.uk/index_lifeexp.php. ; Updated to FF 38.0.1 and the bug had gone.

[#3]

Mine is an older Pale Moon version so the minor bug will remain as I would be loath to change or update.
It's still a bit of a curiosity because of the limited scope of the odd behaviour.

[#4]

Urgh hearing horror stories of FF still misbehaving reminds me to stick with seamonkey.. and i was just thinking of switching to FF too!!!