Within Teamwork Projects, if markdown is enabled on your site, it can affect how numbered lists are displayed.

For example, you might write a message and include a numbered list in the format:

1. Here's the first item in the list:

Here's some more details about the first item in the list, on a new line.

2. Here's the second item in the list:

Here is another line with details about the second item.

Since the "1. 2." list format is recognised in markdown, and the two items in the list above are separated by some text on a new line, this piece of text will be interpreted as two separate lists, and the "2." will be replaced with "1." instead.

The same issue might cause manually numbered lists to be renumbered, if they are out of sequence. For example, you might have:

1. First item
2. Second item
5. Fifth item, since you didn't have a third or fourth

This will be renumbered due to markdown interpretation as:

1. First item
2. Second item
3. Fifth item, since you didn't have a third or fourth 

To avoid this, you can switch off markdown support in the general section of your site settings menu, or you can use a different format for your numbering such as 1- and 2- so that it isn't recognised and processed as markdown.

For more information, see: Enabling markdown