SPSearchContentSource CrawlSetting not applied for ContentSourceType Website

Details of the scenario you try and problem that is occurring:
For Content Sources of type website the CrawlSetting is not configured to crawl only the fist level. Custom is selected instead without limitation.

The DSC configuration that is using the resource:
SPSearchContentSource "ContentSource_$($ContentSource.Name.Replace(' ', ''))" {
Name = $ContentSource.Name
ServiceAppName = $SearchServiceApplicationName
Addresses = $ContentSource.Addresses
ContentSourceType = "Website"
CrawlSetting = "CrawlFirstOnly"
IncrementalSchedule = MSFT_SPSearchCrawlSchedule {
ScheduleType = "Weekly"
CrawlScheduleDaysOfWeek = @("Sunday")
StartHour = "09"
StartMinute = "0"
}
Priority = "Normal"
Ensure = "Present"
PsDscRunAsCredential = $SetupAccount
DependsOn = "[SPSearchTopology]SearchTopology"
}

Version of the Operating System and PowerShell the DSC Target Node is running:
Windows Server 2012 R2, PowerShell 5.1

Version of the DSC module you're using:
1.7

Start at the SPSearchContentSource resource and trace how CrawlSetting is handled for ContentSourceType Website. Reproduce the shown DSC configuration and verify whether CrawlFirstOnly is applied instead of Custom without limitation. Done means website content sources honor the requested first-level crawl setting.