Is there a problem with passwords in 1.2.14?

I administer http://www.classiccarsforsale.co.uk/forums/ - all seems to be going well, or so I thought.

This week I've had a user complain that their password suddenly stopped working, then after they reset it it wouldn't work. They emailed it what it should be and I couldn't get in. I then reset it in the admin panel to on of my choice and it was fine. Since then they have changed it to something memorable, and now it works.

My first thought was this was "user error"

Since then the site owner has contacted me, and said that he too has had issues in the past (of which I remember). Now it is unlikely, but not impossible, that it was user error in this case, as he knows a bit more about PCs and is not stupid.

Are there any reasons why this would happen? Or any known problems?

I know I could upgrade - but am a bit orried that any customisation will go, so don't want to unless there is a reason (such as this, or security) that I should.

Any help, advice ro comments would be appreciated

Many thanks

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