To make it possible to filter and sort Domain Lists on values like Alexa Rank, the data has to be gathered and saved in a Database. This is necessary because requesting values on the fly when a user wants to view the data is to slow. Not only is it slow, but for most resources you can only make a limited amount of requests per minute/hour/day. That is why gathering the information beforehand is so important and that is also why the values you see on the website might have changed.
How ExpiredDomains.net gathers Domain Information
The information for Domains on ExpiredDomains.net are gathered when the Domain gets added to a Domain List.
The information also gets updated after a certain period of time has passed.
This only applies to Marketplace Domain Lists. Deleted Domains do not get rechecked.
The Deleted Domain Lists are more like archives.
The values you see are a snapshot from the time when the Domain got deleted.
This means the older (time from the dropdate) the Deleted Domain is, the more likely it becomes that the data
for the Domain has changed.
The only thing actively updated for Deleted Domains is the availability status. You can read more about how that works here.
Domain Information Updates
Some information can't change like the Archive.org Birth Year. For example the Backlink data can change quite often. A Backlink gets removed, another one gets found or even newly added. Same goes for prices. If the price gets changed on the Marketplace and the List only gets updated once per hour, the price shown to you is not the real price. That is of course not great, but it is unavoidable. The alternative would be not to offer services like ExpiredDomains.net all together and who wants that.
That is why you should always check values you base your decision to buy or register a Domain on. I try to make those checks as easy as possible. Most values in the Domain Listings have links to places where you can check them. Most of the time it is a link to the resource where the system got the information from in the first place, so it should be easy and fast to check them.