Strange Matches error (InnerTemplateStartLine and InnerTemplateStartLine) when linting a specific arm.

I'm running the ARM-TTK linter for a azuredeploy.json listed below and getting this strange error

json-file:
```json
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"privateDnsZones": {
"type": "Array"
},
"virtualNetwork": {
"type": "String"
},
"registrationEnabled": {
"type": "Bool",
"defaultValue": false
},
"location": {
"type": "String",
"defaultValue": "global"
}
},
"resources": [
{
"copy": {
"name": "privateDnsZones",
"count": "[length(parameters('privateDnsZones'))]"
},
"type": "Microsoft.Network/privateDnsZones",
"apiVersion": "2020-06-01",
"location": "[parameters('location')]",
"name": "[parameters('privateDnsZones')[copyIndex()]]",
"properties": {
},
"resources": [
{
"dependsOn": [
"[resourceId('Microsoft.Network/privateDnsZones', parameters('privateDnsZones')[copyIndex()])]"
],
"type": "SOA",
"apiVersion": "2020-06-01",
"name": "@",
"properties": {
"ttl": 3600,
"soaRecord": {
"email": "azureprivatedns-host.microsoft.com",
"expireTime": 2419200,
"host": "azureprivatedns.net",
"refreshTime": 3600,
"retryTime": 300,
"serialNumber": 1,
"minimumTtl": 300
}
}
},
{
"dependsOn": [
"[resourceId('Microsoft.Network/privateDnsZones', parameters('privateDnsZones')[copyIndex()])]"
],
"type": "virtualNetworkLinks",
"apiVersion": "2020-06-01",
"location": "[parameters('location')]",
"name": "dnsforwarder",
"properties": {
"registrationEnabled": "[parameters('registrationEnabled')]",
"virtualNetwork": {
"id": "[parameters('virtualNetwork')]"
}
}
}
]
}
]
}
```

Result form the ARM-TTK linter:

```powershell
2021-12-06 10:32:18 [INFO] File:[/tmp/lint/Policies/PrivateDNSZone/templates/azuredeploy.json]
MethodInvocationException: /usr/lib/microsoft/arm-ttk-master/arm-ttk/Test-AzTemplate.ps1:332
Line |
332 | $InnerTemplateStartLine =
| ~~~~~~~~~~~~~~~~~~~~~~~~~
| Exception calling "Matches" with "2" argument(s): "Start index
| cannot be less than 0 or greater than input length. (Parameter
| 'startat')"

MethodInvocationException: /usr/lib/microsoft/arm-ttk-master/arm-ttk/Test-AzTemplate.ps1:336
Line |
336 | $InnerTemplateEndLine =
| ~~~~~~~~~~~~~~~~~~~~~~~
| Exception calling "Matches" with "2" argument(s): "Start index
| cannot be less than 0 or greater than input length. (Parameter
| 'startat')"

2021-12-06 10:32:31 [ERROR] Found errors in [arm-ttk] linter!
2021-12-06 10:32:31 [ERROR] Error code: 1. Command output:
------

Validating templateszuredeploy.json
AllFiles
[+] JSONFiles Should Be Valid (260 ms)
deploymentTemplate
[+] adminUsername Should Not Be A Literal (28 ms)
[+] apiVersions Should Be Recent In Reference Functions (23 ms)
[+] apiVersions Should Be Recent (82 ms)
[+] artifacts parameter (17 ms)
[+] CommandToExecute Must Use ProtectedSettings For Secrets (23 ms)
[+] DependsOn Best Practices (18 ms)
[+] Deployment Resources Must Not Be Debug (90 ms)
[+] DeploymentTemplate Must Not Contain Hardcoded Uri (62 ms)
[+] DeploymentTemplate Schema Is Correct (8 ms)
[+] Dynamic Variable References Should Not Use Concat (5 ms)
[+] IDs Should Be Derived From ResourceIDs (76 ms)
[+] Location Should Not Be Hardcoded (48 ms)
[+] ManagedIdentityExtension must not be used (5 ms)
[+] Min And Max Value Are Numbers (7 ms)
[+] Outputs Must Not Contain Secrets (13 ms)
[+] Parameters Must Be Referenced (60 ms)
[+] Password params must be secure (9 ms)
[+] providers apiVersions Is Not Permitted (5 ms)
[+] ResourceIds should not contain (14 ms)
[+] Resources Should Have Location (10 ms)
[+] Resources Should Not Be Ambiguous (22 ms)
[+] Secure Params In Nested Deployments (34 ms)
[+] Secure String Parameters Cannot Have Default (4 ms)
[+] Template Should Not Contain Blanks (6 ms)
[+] Variables Must Be Referenced (5 ms)
[+] Virtual Machines Should Not Be Preview (39 ms)
[+] VM Images Should Use Latest Version (2 ms)
[+] VM Size Should Be A Parameter (20 ms)
```

Any ideas what this is? normally this file was linted normally but since yesterday we get this error. (file is not changed)