I'm trying to work out what, if anything, is causing an error. By "if anything" I mean anything that we can possibly fix as players, rather than hoping that somebody at Blizzard happens to see the error and acts on it.
Ever since WoD came out, I've been seeing this error between a dozen and several thousand times a day. The expression complained about on line 1860 is "absorbed and absorbed > 0", but as you can see from the Locals dump further down, 'absorbed' is nil. From other locals (event, originalEvent, missType, etc), you can see that the problematic argument is being passed as the result of the select() call on 2270.
And yes, this error did indeed happen 1084 times on the occasion shown here. Which just goes to show that it's not a corner case; googling finds a few other people reporting the same message.
While there is a global reference assigned to the nominally buggy function (1935), all the call sites are already bound to the local reference by the time any player addon could replace it with a fixed version.