Bug: Marking repeated tasks with two tags as DONE causes problems

[Josh Moller-Mara <jmm@cns.nyu.edu>]

Hello,

I'm starting to encounter a strange, silent problem when switching the
state of a task with multiple tags. With the following minimal example:

#+STARTUP: logdone
#+STARTUP: logdrawer
* TODO Hello :hi:there:
  SCHEDULED: <2017-08-11 Fri .+1d>

Switching The "hello" task from "TODO" to "DONE" should keep the task as
"TODO", but schedule it in the future. Instead, the file ends up looking
like:

#STARTUP: logdone :hi:there:
#+STARTUP: logdrawer
* DONE Hello :hi:there:
  CLOSED: [2017-08-11 Fri 14:57] SCHEDULED: <2017-08-12 Sat .+1d>

Where the task is marked as "DONE", and weirdly tags are added in some
of the startup config at the beginning of the file.

I'm using

Emacs  : GNU Emacs 26.0.50.2 (x86_64-pc-linux-gnu, GTK+ Version 3.22.5)
 of 2017-01-18
Package: Org mode version 9.0.9 (release_9.0.9-746-g8fa6c0 @ /usr/local/share/emacs/site-lisp/org/)

There still seems to be a problem with org-toggle-tag, which is causing
this. I think it has to do with the "replace-match"
again. "org-split-string" doesn't save match data, so "replace-match"
replaces the wrong thing.

Best,
Josh