I noticed that an Eventing function with lots of comments (where the function was made in a 6.6.5 GA version) when imported via the REST API seemed to "gum" up the UI for Eventing making that view non-functional (the target UI with the issue was a recent build Enterprise Edition 7.1.0 build 2175). Note 7.0.3 GA works fine.
I had to use "cbevent -user Administrator -password password -flush -host http://localhost:8091" to get the Eventing portion of the UI unstuck.
Tracking things down it appears that the Function parser is not happy with some text in /* .... */ c-style comments.
The following Eventing Function "f_issue_a.json" can be imported BUT it can not be exported
Note if we drop a '%' character from within the above comment I can perform an export "f_issue_a(1).json" but some funny stuff happens in side to comment.
however in the second case the saved JSON payload in the file system from an export appears very odd insertion of text.
And when I import the exported function "f_issue_a(1).json" then rename it to f_issue_b in the settings I get the following