Addon webItem is not shown in pull request in location "org.bitbucket.pullrequest.summary.actions"

I’ve static plugin that adds WebItem to “org.bitbucket.pullrequest.summary.actions” location.
What plugin does is defining additional button link should appear in the specified location.
On one Bitbucket account the button does appear but on other it doesn’t.
I get error in console see image below: