As described in https://jira.atlassian.com/browse/JRACLOUD-74515, the new issue view does not support more than 120 attachments to a single issue. 

Many users are unaware of this limitation. Nothing stops users from adding more than 120 attachments and many don't notice a problem until the ticket has well over 120 attachments. At this point, attachments are unavailable and cannot be downloaded.

I propose having a pop up that warns users that they are approaching the 120 attachment limit and/or a mechanism that prevents any more than 120 attachments from being added to a single ticket.