Remote Github repository search does not work

When browsing for remote repositories, SourceTree nicely shows the list of all available Github repositories for my account. When I enter text in the Search box however (text that I know should give me a match), the list goes empty and a red cross icon overlay appears on my Github account. As soon as I clear the search box, the icon overlay dissappears and I get the full list of repos again. Since we have a large amount of repos the search is quite important.

Note: my SourceTree Windows version is actually 3.3.8, but Jira doesn't allow me to select that version.

Reproduction

• Open a new tab
• Click on the Remote button
• Select the appropriate Github account from the list of remote accounts
• Watch the list of Github repos populate
• Enter text in the Search box that should return a match

Expected result

• The list of repositories is filtered by the entered text

Actual result

• The list of repos turns empty
• A red cross icon overlay appears on top of the Github account gravatar
• A hover over of the red cross shows mentioning ... validation failed ... (see image)