I have tested in my SharePoint search and could not reproduce the issue.
First, I uploaded a file named "test-file" in the document library.
Then, I did a full crawl, it crawled successfully.
Could you provide some screenshots about files and crawl logs?
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.