calc - "To paste outside Nextcloud Office, please first click the 'download' button"

Describe the bug
When copy-pasting from Nextcloud Office calc, I often get an error message when pasting the content elsewhere (i.e. local text file): To paste outside Nextcloud Office, please first click the 'download' button

1. the phrase please first click the 'download' button is very misleading in this context - there is no download button! What does this mean in this context? Confusing for the user.

2. This behaviour is... seems intermittent: on the same internet connection it occurs for some copy-paste tasks, but not all. Given I'm typically copy-pasting text from calc cells, this seems inconsistent and unnecessary?

issue has been persistent for 1 year+

To Reproduce
Steps to reproduce the behavior:

1. open calc doc w lots of text in cells (i.e. social media-length text, ~280 characters or more)
2. double-click a cell into edit mode
3. select all text (ctrl-a)
4. copy (ctrl-c)
5. paste into text editor locally

Expected behavior
Paste the text in clipboard (i.e. the text that was copied from the cell)

** Actual behaviour **
text pasted is: To paste outside Nextcloud Office, please first click the 'download' button

Screenshots

Client details:

• OS: Linux desktop (NixOS 24.11)
• Browser Chromium 128.0.6613.119
• Device: desktop

Server details

Operating system:
Ubuntu 22.04.4 LTS

Web server:

Database:

PHP version:

Nextcloud version:
30.0.0

Version of the richdocuments app

Version of Collabora Online
24.04.5.4

Configuration of the richdocuments app

Insert the output of `./occ config:list richdocuments` (or equivalent adapted for your runtime environment)

Insert your Nextcloud log here

Insert your browser log here, this could for example include:

a) The javascript console log
b) The network log
c) ...

Start by reproducing the copy-paste steps in a Calc document with longer cell text, using the reported Nextcloud, Chromium, and Collabora versions. Inspect the browser and Nextcloud logs, which are not provided, to determine whether the message originates in the integration or Collabora Online. Done means the copied cell text pastes locally reliably and the misleading message no longer appears.