Autothrottle disconnect engines to idle

[WallyWalt]

Hi, I experienced something today that I didn't recognise before, or it didn't happen. On approach to CYYZ I disconnected the autothrottle about 100 feet above ground. The engines didn't hold the power setting, but immediately spooled back to idle. I haven't flown the A310 for a while, but I'm pretty sure the engines stayed at the N1 value they had before I disconnected the autothrottle on my last flight. Could replicate the issue with several (shorter) flihgts afterwards, repro 100%.

Is this true to life or a bug? Can you have a look at this?

Thanks, Walter.