Prove right to work website shows tier 2 visa shortened , HELP!

Hi,
I have tier 2 general valid till dec 2021 and I have only 1.5years left to apply for ILR. Recently one of my colleague mentioned about https://www.gov.uk/prove-right-to-work website which shows how long person is allowed to work in UK by entering their BRP number. I have tried my brp number and it showed that I am allowed to work only till November 2019 with a message at bottom as "the date maybe different to what's printed on your card because your leave is shortened". You could understand my total panic at this stage, because for other people with brp it showed their correct validity date and for me it's different. I alerted my HR about this and she contacted home office and they have no clue about this and can't help in any way. They asked to write a letter to Sheffield home.office with the issue and wait for reply. I haven't received any letter saying that my tier 2 visa is shortened and neither does my employer got any notification. I have my brp which says Dec 2021,but the website says otherwise and my HR is worried now as whether I am legally allowed to work after November 2019. Can anyone help if they had similar situation?

Update: HO replied that it was an error and they generated the shortened visa date when they got notification from my previous employer that I left the job and it generated curtailment as soon as they got that notification and it reflected on the system. But by that time, I am already with my current sponsored employer with new validity date and they didn't pursue with curtailment (probably failed to update the file and remove the shortened visa date). and assured that my current brp date is valid.