Content of field "Type" disappears when saving

I have been using JabRef for a long time and never had this problem before: I use the entry type “TechReport” to store discussion papers and put all the bibliographical info in the field “Type”, e.g.: “{CESIfo Working Papers No. 6224}”. This used to work fine.
Today, I found out that it does not save whatever I write into “Type”. The content of this field disappears the moment I press the save button.
Has anyone experienced this problem before? (Or is this on purpose and I’m just doing something wrong?). Thanks!

Thanks for your report! You have discovered a bug, I suggest it is a problem with the combobox for selecting the types is linked to the field.

A workaround would be to enter the field type = { your working paper no 23} in the source tab. And you don’t have to touch it in the type field. The moment you click in the type field again it will be overwritten.

I have opened an issue at github: