Type properties panel bug
Every time when changing a text's properties and deselecting it the text is reverted to size 12. Also when a different colour is applied to part of the text and deselecting it, the colour is applied to the whole text. The situation is the same with different font styles - setting part of the text in bold will result that everything is changed to bold when deselected. It happens every time.
We have the fix available in the latest release. Please update Illustrator using Adobe Creative Cloud application to the latest build for version Illustrator CC 23.0.
Please refer to our knowledge base FAQ – https://illustrator.uservoice.com/knowledgebase/articles/1844590 if you face difficulty in update.
Or get in touch with us at any of the other support channels – https://helpx.adobe.com/support.html
Ashutosh Chaturvedi | Sr. Quality Engineering Manager – Illustrator
Adobe. Make It an Experience.