UMLR — Message lines can cross without the first being asynchronous

In the description of Figure 17.3, where the messages of CardOut and OK cross before they are received, the description says.

"Such communication may occur when the messages are asynchronous"

Though this true, it is misleading. It's possible for the messages to cross even if the messages are synchronous. The sending lifeline may have multiple parts (or multiple threads), where each part (or thread) waits synchronously, the overall effect on the composite level is to look asynchronous. This was extensively discussed last year and the conclusion was that this was possible.

Please eliminate the offending sentence