Is anybody familiar with ERROR c.s.whd.service.impl.CsrfServiceImpl - incorrect URI syntax

We recently updated to 12.8.1 (HF1) and are frequently seeing the following set of errors in our logs. This can happen when there are zero other clients or techs, including in our test environment, but we are unable to replicate it when we try. It seems to come in triplicates.

2024-04-19 01:54:17.480 [https-jsse-nio-443-exec-12] ERROR c.s.whd.service.impl.CsrfServiceImpl - incorrect URI syntax /helpdesk/WebObjects/Helpdesk.woa/wo/</b> ... <b>, message
2024-04-19 01:54:17.480 [https-jsse-nio-443-exec-12] ERROR com.macsdesign.whd.ui.Application - Application.handleException(): com.webobjects.foundation.NSForwardException [java.lang.UnsupportedOperationException] incorrect URI syntax:java.lang.UnsupportedOperationException: incorrect URI syntax
com.webobjects.foundation.NSForwardException: java.lang.UnsupportedOperationException: incorrect URI syntax

.... 

2024-04-19 01:54:17.527 [https-jsse-nio-443-exec-12] ERROR com.macsdesign.whd.ui.Application - UNHANDLED EXCEPTION:
java.lang.UnsupportedOperationException: incorrect URI syntax

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