Input tax visible in 2A but not in 2B

Hello,

If I have eligible input tax for April month visible in GSTR2A under B2B invoices and not 2B. In GSTR2B I get the following message:

GSTR-2B is being generated and should be available by 14/05/2023. Either you do not have any records in GSTR-2B or the generation is still in progress. If you are still not able to access it, please raise a ticket with GST support team.

Also, I realized under 2A that the supplier has filed his April months GSTR1 on 12 May. 

Is it because supplier has filed GSTR1 on 12th April or is it something else? Can I claim input tax for invoices visible in 2A but not 2b?

Thank you in advance!