yes , its true since the paper 2 is to get admission in architech so in which you need to qualify the paper 1 and as the other phase of paper 1 is still yet remaind to be completed in the april phase so some people may get qualified in april phase but get failed in the jan phase exam so they will be also eligible to get BArch so definetly the result will be on april only

There are no official announcements by NTA   for the Jee Main paper-2 (B.Arch and B.Plan) (Jan) results yet, but it is supposed to be released on 31st January.

The results of Jee Main paper -1(january) has already been announced on January 19 and the results for the Jee Main April session will be announced in April for paper-1 and for paper-2 as well. Here's a link where you can read more about it  https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-paper-2-result/amp