I have set up an instance of thermostat scheduler, it works fine.
I also have a Rule 5.1 app that sets that TS scheduler instance to HOLD at a certain time of the day.
I am not sure when this became an issue, I just noticed in the last month or-so as the warm season gets going, it's not HOLDing the TS scheduler during that time.
Looking closer, I see this in the Rule 5.1 app logs:
Need to call in the developer. @bravenel I cannot see why this rule would be trying to convert anything "toLong" when it is trying to set the hold status?
Please open the App Status page for the rule (gear icon upper right in rule). At the top of that page are Settings, one of which should start with "thisApp" -- could you show a screenshot of that portion of the App Status page.
I can't find any problem with this in my testing, so I'm not at all sure what is going on. My suggestion is to try this: Remove those actions that set Thermostat Scheduler, and create them again. See if that fixes it or not, and let me know.