This appears to be a bug in the ZAPI being used by PSTK, or at least the documentation so that consumers (e.g. PSTK) know what output to expect. To dig a little deeper, here is the ZAPI output from my ONTAP 9.1 cluster:
<results status="passed">
<attributes-list>
<security-login-role-config-info>
<account-expiry-time>unlimited</account-expiry-time>
<account-inactive-limit>unlimited</account-inactive-limit>
<change-password-duration-in-days>0</change-password-duration-in-days>
<delay-after-failed-login>4</delay-after-failed-login>
<last-passwords-disallowed-count>6</last-passwords-disallowed-count>
<lockout-duration>0</lockout-duration>
<max-failed-login-attempts>0</max-failed-login-attempts>
<min-passwd-specialchar>0</min-passwd-specialchar>
<min-password-size>8</min-password-size>
<min-username-size>3</min-username-size>
<passwd-expiry-warn-time>unlimited</passwd-expiry-warn-time>
<passwd-min-digits>0</passwd-min-digits>
<passwd-min-lowercase-chars>0</passwd-min-lowercase-chars>
<passwd-min-uppercase-chars>0</passwd-min-uppercase-chars>
<password-expiration-duration>unlimited</password-expiration-duration>
<require-initial-password-update>false</require-initial-password-update>
<require-password-alpha-numeric>true</require-password-alpha-numeric>
<require-username-alpha-numeric>false</require-username-alpha-numeric>
<role-name>vsadmin</role-name>
<vserver>qtest</vserver>
</security-login-role-config-info>
</attributes-list>
<num-records>1</num-records>
</results>
The error I'm receiving is saying that it can't parse a string into a number for the value of account-inactive-limit. If we look at the ZAPI docs it says it's a string type with an integer value:

In the ZAPI response above, notice that the value is "unlimited"...which is not an integer. PSTK is using the function System.Number.StringToNumber to attempt to convert that into an integer, which fails and is causing the error we are seeing.
I'll create a bug to track this. If you're willing to PM me your address, I'm happy to send you some stickers as a bug bounty 😄
Andrew
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