Inconsistent railing treatment at landing stringers

[CEdwardsUN5MX]

I've developed a post (balustrade) to work with stringers, and this works fine, some of the time.

It's really bugging me that it is inconsistent, and I can't figure out why.

Attached screen shots show the balustrade base adjusting to suit the stringer at a landing, and along the stair. At one landing however it simply ignores the stringer, so the base of the balustrade is at the landing level, not set up the necessary distance on top of the stringer.

The railing is set to adjust for landings though.

I've attempted to model this from scratch using select the path and got the same result. I've reattached to the host and same result.

No idea what is happening or how to fix an inconsistent problem with no clear cause.

Suggestions?

Revit family for the balustrade attached.

[barthbradley]

Seems to work here. Post your Project File (RVT).  

[CEdwardsUN5MX]

Model file is > 1Gb unfortunately.

I've done a cut and paste into a blank project and annoyingly it works fine picture below).

But I can't cut and paste back without the same problem. Something in the project environment....?

[barthbradley]

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@CEdwardsUN5MX wrote:

Something in the project environment....?

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That's what I was thinking.  Hard to troubleshoot with seeing the RVT itself.  

[ToanDN]

Do a save as to another file, delete everything except that one stair and railing, then share it here.