Different URL for the Same Record When Edit is Cancel

When I select a record from a table I see the following link:
https://********.quickbase.com/db/bpdyd4kbj?a=dr&rid=5&rl=crz
I can clearly see the record id ("5")
If In this record I click "edit" and then in edit mode I click Cancel to exit edit mode the new url for the same record is the following:
https://********.quickbase.com/db/bpdyd4kbj?a=dr&r=f&rl=crz

Now record id information is encoded as f  (r=f))(a=0,b=1,c=2,d=3,e=4,f=5...). Why is this happening? Why we cant have the same first url? This complicates the creation of some types of scripts. Also I haven't been able to figure it out the letters encoding:

I have a record with rid = 2536 that is encoded  as "cri" in letters, and  2535 is "crh". If somebody knows the formula of the encoding please let me know. (it is not as simple as base 26, unless I made some mistakes)

Thank you.