Wonder if someone could help.
I'm doing an Insert edit to a studios dub of one of my show. The insert
is on Digi Beta using A500 on a Symphony Nitris. When I do the insert
I'm getting really bad pixelated digital hits on the head and tail of
the insert.
I have done the same insert to 5 other tapes with no problems. The only
difference I see to this one tape is that whoever did the dub pulled up
my blacks in the show.

How are the channel conditions on playback? You may have a bad tape caused by various reasons (bad ref, bad heads, bad cable, etc, etc). Check the channel conditions first. Then check the usual suspects (ref, termination, head cleaning, etc.)

 I'm having an almost identical problem with MCA and Betacam SX digital. When attempting an insert, I get a single black frame at the beginning and end of the insert. Basically, the insert edit function is useless to me. It doesn't matter what tape stock or if a different deck is used, the result is the same.

 Checked the tape condition thats fine. Everything is sync in Ref.Still getting digital hits on the tail side of the insert. Going to try and clean the heads.

 Larry, the 720p insert edits will give the frame of black on the "in" but the out should be fine.  Hmmmm

 We're still an SD house, all of our projects are 30i.

 Looks like a calibration issue with a dub houses deck and mine.

 Ahhhhhhhhhh, SD, well that's a kettle of fish, ain't it?  Cheers.