[PIF]

Your field museum link - bottom maps show mainland connection
This map around 12,000 BC shows and earlier or later time period than this next one

This map shows a connection between Greater Sulu and Borneo

Notice the small gap in this reconstruction between Greater Palawan and Borneo during the Older Dryas Period, which if memory serves was a time of falling sea levels circa 14,000 years ago which makes it positively modern compared to 700,000 ya

During the time show on the above maps, it would have been easy to cross. Anyway, I think you'd have to look at some specialized academic sea level maps to find anything prior to 20,000 ya.

So my original assertion could be wrong; there's no telling apparently. There does not seem to be much on sea levels during the start of the Paleolithic Age in Asia or anywhere else I could find. If it exists, it is not published yet.

At 14,00,000 ya that area does not look to have emerged from the main land masses FWIW.

[SunkenCiv]

Since the artifacts are much older — 700K — and there’s info in the text that the water was deeper farther back in the Pleistocene, it remains to be seen that there was a land bridge.