Click on the assignee here https://jira.atlassian.com/browse/FE-115
then click on her "User Filters - Assigned - all" link on the RHS.
The original issue in issue (FE-115) does not appear in the list.

I don't know if this is the root cause, but I assigned that issue to her from the Edit Issue screen. After hitting Submit, the POST was taking a while, and I might have clicked-away (ie I went to another page before the http response had (fully) returned).
Perhaps that interrupted the indexing that JIRA performs on each issue update?