Firstly, the discrepancy that you observe with the position on chr2 is due to different genome reference builds:

• chr2:85882623 = GRCh38 / hg38
• chr2:86109746 = GRCh37 / hg19

Merging of records FAQ

Yes, the merging of records is more common than you may imagine. There is a FAQ on the merging of dbSNP rs IDs here: https://www.ncbi.nlm.nih.gov/books/NBK44468/

All merged dbSNP records

In addition, here is a search configuration that lists all dbSNP rs IDs that have been merged: https://www.ncbi.nlm.nih.gov/snp/?term=mergedrs (the option to download the data is on that page - see 'Send to' at top-right).

Same dbSNP, multiple positions

You should also be aware that quite a few dbSNP rs IDs are duplicated and have different positions in the same reference genome build. Take a look at the reason here: https://www.ncbi.nlm.nih.gov/books/NBK44455/#Build.why_does_rs3823342_have_two_differ_1

Good luck and trust that this helps.

Kevin