This is unexpected, I mean, Toolset wouldn't change the address you added.
I have a personal website as well built years ago with such feature and I just checked, all addresses that I entered with valid Google Addresses are still there and can be found in searches.
Logically Google can't find a Lat/Long address by a City name, but you should be able to find that spot, by filtering let's say 50km from a city name - given the lat and long specified place is within those 50km.
However, Toolset does A) Not convert addresses from valid to invalid or lat/long only. It also offers no mechanisms to somehow invert this, because a lat-long location is never an address. A lat/long location could be just 2 meters next to the actual "address" that google offers, and yet it wouldn't be that address, that's why you would use a Lat. and Long. in these cases.
Often Toolset Maps then also offers a "pick this address" in the map when adding new lat and long location, if there are any closeby Google Suggested Locations, but that is all, no other conversion is done.
Checking the URLs in your examples, I see that one searches 50km within "Bologna, BO%_vmit_cmit"
This is certainly not a valid address.
This is what Google itself returns on that search; hidden link
It suggests a mistake. Is the query correct? I think it should be Bologna, BO?
I see however that this doesn't work either on your site:
hidden link
It shows ALL results, not the ones only within 50km of the centre
That is surely unexpected. I see that when running the query by Lat Long... it works. 🙂
While that's fine, I would surely expect the search to also return anything located within 50 km of a NAME of a city, why would I have to guess the Lat and Long, even if the addresses are saved in that format?
Indeed, that is just how it works on my tests! So, this must be some sort of exception, or I miss a step in the replication of the issue.
You mention this worked in past. That's helpful.
Can you recall when it started breaking? The precise update? That would allow us to make more precise tests as well.
Finally, I think the easiest is - if you can confirm this issue to happen as well with only Toolset and Theme Twenty Twenty - (maybe on a testing site) to send me a copy of this site following https://toolset.com/faq/provide-supporters-copy-site/ instructions
I can then dig into the setup and hopefully locate the issue, so the DEV can solve it, or update you with a resolution