Error in TinyMCE when typing %-character

[Arriba99]

Preconditions

1. Magento 2.1.3 CE
2. PHP 5.6.21

Steps to reproduce

1. Open product or page
2. Type %-character in TinyMCE Editor field

Expected result

1. Everything should be fine

Actual result

1. Immediatly an error is displayed (2 times):
   error: error in [unknown object].fireEvent(): event name: tinymceChange error message: malformed URI sequence

Once the %-character is typed in the editor, the error pops up again everytime you type in the editor field. All other characters doesn't trigger the error. When the product or page is saved, the %-character gets deleted in the text.

We use another magento installation for testing and there the error doesn't show up.

Kind regards!

[fxdegroot]

We got the exact same problem on Magento 2.1.4 EE

[hostep]

That's really strange, since the code which causes this problem is only active in the develop branch and not in a previously released version. See #9452 for more details.
Although the error message is slightly different (malformed URI sequence vs URI malformed), so maybe this is then a different issue?

[veloraven]

We already have internal ticket for ver. 2.1 - MAGETWO-68810