Lucee does not support the group parameter on the <cfschedule> tag, an error is thrown with the message: "Attribute [group] is not allowed for tag [cfschedule]".
The group parameter is supported in Adobe ColdFusion 11, 2016 and 2018.
Whilst full support for the parameter is desirable (to group common or related tasks), it would be enough to just not error when the group parameter is present. Otherwise it would be necessary to maintain two different codebases for Lucee and ACF.
CFDocs shows the [group] parameter as supported.