JST-310000 Error while compiling script 'content htmlContent' line 41: recipient.relClientVehicule_client.vehicule is undefined.
The error you observed is a timeout issue when the workflow is trying to contact the deliverability server for fresh rules.
As there is a single deliverability server present for Adobe and all Adobe customers connect to it for new data, at times the web module gets overloaded on Adobe Servers and it results in a timeout. The code of this workflow when executed puts the current execution in a pause of XXXX seconds. This value is determined randomly and hence all our customers get a different wait time but still at times it cause bottleneck on our side leading to issues.
First step to try here is to restart the workflow manually and force execute it to see if it works then.