In an attempt to simplify the process, I have tried several combinations of chained timers (start timer event or start event leading to an intermediate timer event) and single repeating intermediate timers and could not recreate this issue. However, I see other unexpected timer behaviors for which I will create separate issues as needed. I can only recreate this particular issue with a task boundary timer event triggering an intermediate timer event (see attached unit test and corresponding process template).
Note that this scenario covers the business use case for sending a notification at a different timer interval from the repeat intervals (i.e. send 1st at a longer time period, with additional reminders at shorter time intervals).
Windows 7 Enterprise SP1, Tomcat 7.0.42, standalone H2 db (tcp url, not embedded)