I found a similar issue but couldn't understand any action to take. I have two open-source scala libraries - I published the second one just yesterday. Everything looks good on the Bintray repo, but only one version makes it to jCenter.
https://dl.bintray.com/ticofab/maven/io/ticofab/ :
aws-request-signer_2.10/
aws-request-signer_2.11/
aws-request-signer_2.12/ <-- latest scala version, missing later
reactive-kraken_2.11/
reactive-kraken_2.12/ <-- latest scala version, missing later
http://jcenter.bintray.com/io/ticofab/ :
aws-request-signer_2.11/
reactive-kraken_2.11/
Is there a way I can solve this? Thanks.