SYSML2_ — TransitionUsage source and target properties do not support feature chains

According to the SysML abstract syntax (8.3.17.9 TransitionUsage), the source and target of a TransitionUsage must be ActionUsages. However, the textual notation (8.2.2.17.3 Transition Usages) allows sources and targets to be feature chains, which are parsed as a KerML Feature with FeatureChaining relationships to the chained Features, which are not ActionUsages.