Samba share data missing

I have to correct myself. That behaviour happen on iPhone too…

But other Apps (for example File Explorer) report a correct situation

SMB connections in the Files app have been very unreliable for me in the past.

It works fine immediately after connecting to an SMB server, but as soon as it gets disconnected, it won't reconnect reliably. You need to recreate the SMB connection in the Files app and add it to Textastic again to make it work again when it is in this state. This is something out of my control that Apple has to fix.

I wouldn't recommend using SMB shares with the Files app. I have seen the problem you are describing as well as hangs when using the iOS Files app's built-in SMB client (not related to Textastic, reproducible in other apps like iA Writer). Instead, I recommend to use Textastic's built-in SFTP client:

https://www.textasticapp.com/v10/manual/remote_servers/sftp_ftps_ftp.html

https://www.textasticapp.com/v10/manual/remote_servers/uploading_downloading.html#quick-uploading-and-downloading

If you need live editing, I can recommend the app "Secure ShellFish" which allows you to connect to SFTP servers from the Files app and works great with the external folder feature of Textastic (the app's "Pro Unlock" is required for uploading changes):

https://apps.apple.com/de/app/ssh-client-secure-shellfish/id1336634154

https://www.textasticapp.com/v10/manual/integration_other_apps/external_files_folders.html#adding-external-folders