I opened a GEDCOM in Family Historian that I had exported from FTM. Everything seemed fine until I tried to use the FH-modified GEDCOM on my web site. All of the custom event tags had been changed from EVEN to _ATTR. Unfortunately, the software that I use for my web site (TNG) looks for EVEN for custom events.
In the FH Event/Attribute List they are shown as Type = Event.
ID:4244
* Migrating from Family Tree Maker
Migrating from Family Tree Maker
I have solved this problem. I used notepad to find and replace all _ATTR with EVEN in a GEDCOM copy of the FH file. I used that version for my website.