Except this 2am, 4am arrival is not really mis-coding of a stay and is likely to occur at many hotels and not just with IHG brands. So often reported I fail to see why yet another OP feels need to generate yet another new thread on this exact same subject

It occurs because
1. Hotełs will not check you in until you physically turn up, whether you email to say 4am flight arrival etc or not
2. At some early morning time , say 2am the hotel night auditor runs the accounting procedure for that nights stay , closing out your room as not stayed in on cheKcin day
4. You arrive 4am, 6am or whatever after night audit reset is run, hotel recognises you hold a valid reservation for night before through to noon.
Hotel honours reservation and checks you in as a DAY RATE, and with IHG day rate is always posted as a non-qual stay as per IHG rules
(Note HILTON day rate stays are qualifying though you sometimes need ring HH Helpdesk if posting as nonqual)
5. As in hotel system as a day rate post night audit run , many hotels lack possibility to correct. Contacting IHG Helpdesk after stay posts will result in Helpdesk manually correcting and posting the missing night stay/night credit


...... And yes some hotels will bookin into rooms late arriving guests late arriving (even no shows ) and prepare key packs, charge provided CC, as night desk cover person may lack access to perform those checkins and run night auditor report is executed right then. Night cover just checks guest I'd and hands over keypack
Such hotels usually then manually next day's set uncollected keypack rooms as noshows so no points/qual nights inadvertently issue during