Your comments

Thanks for letting me know about this issue. I'll try to reproduce it.

Do you know steps to reliably reproduce the issues you are seeing or does it only happen sporadically?

Thanks a lot for your feedback. I'll see what I can do in a future update.

As a workaround, you can navigate to the folder in the Files app. This seems to trigger a download.

I can reproduce the issue. I'm pretty sure this used to work in earlier versions of iOS. I'll try to find out what's going on.

Thanks for letting me know!

If you deleted the app and redownloaded it, the files in the "Local Files" folder will be gone unfortunately. 

If you have a recent backup of your iPad in iCloud, you might be able to restore your files using that. But be careful since all data changed since the backup will be lost when you restore the backup. 

Can you please try if a reboot of your iPad helps?

How exactly are you trying to open the .c files stored in iCloud Drive?

If you use the "Open…" command in Textastic, you should be able to open the files.

If you have multiple files in the same iCloud Drive folder, you can use the "Add External Folder" command in Textastic to add the iCloud Drive folder as an external folder to Textastic.

Please have a look at the following topics in the manual for details:

https://www.textasticapp.com/v9/manual/integration_other_apps/external_files_folders.html

https://www.textasticapp.com/v9/manual/managing_files/local_files_icloud.html