I am having this issue on US-bound itineraries. When you say I should not be concerned, is that because you think it is random, will resolve itself, something else?
Because it gets resolved itself by either the contractors or DHS without the passenger having to do anything and/or because even the quota “random” inclusions mean that some people will have 3 or more back to back selections on US-bound international flights because that just happens to some due to the selection process for meeting the quota.
Flying the same carriers a lot on which you’re getting SSSS a lot can eventually help to reduce the chances of being flagged going forward. Even when the selection is because of what DHS or the contractors are using that involves identity confusion.