Based on the wiki, there are two recent (August 28) articles specifically about this: "Rams news: Sean McVay on Puka Nacua suspension after Tutu Atwell trade" and "Sean McVay: Tutu Atwell trade had 'nothing to do' with possible Puka Nacua suspension" (per the Tutu Atwell page). So yes, there's a "possible" suspension floating around, but the wiki doesn't give details on what it's for or whether it's likely.
What it does say clearly: Sean McVay explicitly said the Tutu Atwell trade had "nothing to do" with any potential Puka Nacua suspension. McVay directly separated the two issues — suggesting the Rams aren't bringing Atwell back as insurance for an absence. The Nacua page also notes his contract extension is "at risk" due to "recent off-field issues," which could be related to whatever suspension chatter is happening.
Bottom line: The wiki confirms rumors of a possible suspension exist, but doesn't confirm a suspension is actually coming. Atwell's return was explicitly not tied to that possibility per McVay.