TextToolbar ordered List numeration error

I'm submitting a...

Bug report (I searched for similar issues and did not find one)

Current behavior

When using a Ordered List in Rich Text format, the numbers jump from "9", to ":" and then "21" (First attached Image), and repeats the same every 10 elements.

When on Markdown if you insert ten elements and apply the ordered list property, but delete the first two, in the text editor your list will start with the number 3, while the Markdown Preview will start on number 1(Second attached Image).

Expected behavior

It should order the numbers correctly.

Minimal reproduction of the problem with instructions

When Opening the sample app, go to Control -> TextToolbar, press the ordered lists button, and insert more than ten items.

Environment

Nuget Package(s): 5.0.0

Package Version(s): 

Windows 10 Build Number:
- [ ] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [ ] Insider Build (build number: )

App min and target version:
- [x] Fall Creators Update (16299)
- [ ] April 2018 Update (17134)
- [x] October 2018 Update (17763)
- [ ] Insider Build (xxxxx)

Device form factor:
- [x] Desktop
- [ ] Mobile
- [ ] Xbox
- [ ] Surface Hub
- [ ] IoT

Visual Studio 
- [x] 2017 (version: Community 15.9.5 )
- [ ] 2017 Preview (version: )