Hi General ,
Welcome to this Microsoft Project newsgroup
I think more of an anomaly that a bug

It depends on the exact number of
minutes you choose. For example, if you have 1ed, that equates to 24
ehours. If that task has a predecessor with a normal 1d duration that
finishes at 1700hrs, then the 1ed task will start 1700hrs and finish at
1700hrs the next day, though the elapsed nature of the task is continued via
the logic link to the time the following task begins. However, the next task
cannot start until 0800hrs the following day which gives the elapsed time
task a .63eh of slack - ie not critical. If, however the first task begins
a 1.2d task at 0800, it will end at 0936, allowing the elapsed time task to
start at 0936 and finish at 0936 the next day whence the following linked
task can begin - ie zero slack and thus critical and red. It's easier to
see this by experimenting with a few tasks, showing times in the Start &
Finish columns.
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Hope this helps - please let us know how you get on

)
Mike Glen
MS Project MVP