In an automated update, the Mac App Store Uodate page initially shows buttons labelled Update against each app which is due for an update. However, one of these has already started updating. But it doesn't say which one. I guessed which app had started updating, and hit the Update button for that app in the Mac App Store update page. I then waited a long time - many minutes - for the Mac App Store page to refresh. When it did eventually refresh, it gave me a download bar for the auto-updating app, saying that a GByte had already downloaded, and the Update button had turned into a Pause button. I then had to hit that twice, but it did eventually pause the download.

In an automated update, the Mac App Store Update page initially shows buttons labelled Update against each app which is due for an update. However, one of these has already started updating. But it doesn't say which one. I guessed which app had started updating, and hit the Update button for that app in the Mac App Store update page. I then waited a long time - many minutes - for the Mac App Store page to refresh. When it did eventually refresh, it gave me a download bar for the auto-updating app, saying that a GByte had already downloaded, and the Update button had turned into a Pause button. I then had to hit that twice, but it did eventually pause the download.