Resource scanners can have configured settings that should be retained in blueprints.
Currently scanners placed from a blueprint will report the default settings, instead of the {x, y, width, height, filter} they were blueprinted with.

Being able to retain settings in blueprinted scanners is necessary for building that self-replicating factory.

I think the bug could be here, where tags = event.tags is being overwritten and copied from the clone settings, that could mistakenly be nil.
https://github.com/FoxLBA/factorio-bad-chest/blob/master/lualib/scanner.lua#L105-L110

No. The problem is in the Factorio API.
When saving a blueprint, the mod is not always passed a link to the blueprint object with which the script needs to interact. Because of this, it is basically impossible to save any additional information in the blueprint.
Saving settings in blueprint has the following limitations:
1. Saved/modified blueprint-item must be in the hand/inventory (i.e. not in the library and not in the book).
2. The blueprint should not contain entities with saved settings/information from other mods.

Being able to retain settings in blueprinted scanners is necessary for building that self-replicating factory.

Nah, just wiring a constant combinator to the scanner should work, right? The settings are then saved outside the scanner.

Or are scanners not accepting signals with default configuration? If so, that is fixable by FoxLBA to have defaults that accept wire signals.

I changed the default settings of the scanner.
Now I'm thinking of getting rid of the flexibility of the scanner in terms of incoming/outgoing signals.
But I am hindered by backward compatibility support. =\

Heya FoxLBA,
As one software engineer to another I have empathy for the trouble this bug fix has caused with backward compatibility and initial groking use of this mod.

But I want to show off what fixing this bug has accomplished:
https://factorioprints.com/view/-Neq6_E_muEZey9Lpjwg

Thank you for your help and adjustment, and I apologize for the belated thank you. This is a great mod and you are a baller 🤘

But I want to show off what fixing this bug has accomplished:
https://factorioprints.com/view/-Neq6_E_muEZey9Lpjwg

I would like to see a video this! You could make a new thread specifically for announcing the showcase video. :)