Qubes-template-manager sometimes does not update its output

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Qubes OS release

r4.3-rc3

Brief summary

Qubes-template-manager sometimes does not update its output. Example:

This has been showing for a while now, while template installation is certainly under way (I can see the template starting and shutting down).

Steps to reproduce

Install/upgrade a template. This does not happen always, I'd say around once in 5 tries for me.

Expected behavior

Text updates.

Actual behavior

Text does not update, even after template installation is fully completed. This makes it difficult to tell when a template has fully finished installing.