Hello, all!

In some moment we start to see strange error in our logs:

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com.pega.pegarules.pub.generator.UnresolvedAssemblyError

com.pega.pegarules.pub.generator.UnresolvedAssemblyError: Invalid expression or reference: No suitable instance found [seeking]  @(Pega-RULES:Utilities).LengthOfPageList(ClipboardProperty) [candidate functions are]

    at com.pega.pegarules.priv.FUAUtil.throwUnresolvedAssemblyError(FUAUtil.java:423)

    at com.pegarules.generated.expressions.ra_action__pxactorscount__0268e1b260fc5d6fa92c75fa9441927a.perform(ra_action__pxactorscount__0268e1b260fc5d6fa92c75fa9441927a.java:113)

    at com.pega.pegarules.session.internal.mgmt.Executable.doAction(Executable.java:3305)

    at com.pega.pegarules.exec.internal.declare.infengine.ChainingEngineUtilImpl.runActivity(ChainingEngineUtilImpl.java:227)

    at com.pega.pegarules.exec.internal.declare.infengine.ChainingEngine.processVariableChanges(ChainingEngine.java:1027)

    at com.pega.pegarules.exec.internal.declare.infengine.ChainingEngine.forceFeedProcessVariableChanges(ChainingEngine.java:524)

    at com.pega.pegarules.exec.internal.declare.infengine.InferenceEngineImpl.invokeForwardChaining(InferenceEngineImpl.java:592)

    at com.pega.pegarules.exec.internal.declare.infengine.InferenceEngineImpl.forwardChain(InferenceEngineImpl.java:637)

    at com.pega.pegarules.exec.internal.declare.infengine.InfEngUtilsImpl.forwardChain(InfEngUtilsImpl.java:885)

    at com.pega.pegarules.exec.internal.declare.infengine.InfEngUtilsImpl.forwardChain(InfEngUtilsImpl.java:914)

    at com.pegarules.generated.activity.ra_action_triggercheckcache_22da3dfe6236a94d14c9856040fd6d28.step1_circum0(ra_action_triggercheckcache_22da3dfe6236a94d14c9856040fd6d28.java:248)

    at com.pegarules.generated.activity.ra_action_triggercheckcache_22da3dfe6236a94d14c9856040fd6d28.perform(ra_action_triggercheckcache_22da3dfe6236a94d14c9856040fd6d28.java:69)

    at com.pega.pegarules.session.internal.mgmt.Executable.doActivity(Executable.java:3500)

...

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This error appears in PegaRULES log when user tries to login.

User see error message

>>There has been an issue; please consult your system administrator

After F5 error message disappears and normal portal is shown.

Also BIX command line extracts stops working without any error messages in logs - log files just abruptly ends before usual messages about instances count.

Attempted solutions:

-Reboot with extract marker removing - no effect

-Clear every possible cache in SMA - no effect

-Resave pxActorsCount declare expression to our application ruleset - it elliminates problem for this application users and cures half of BIX extracts. Remaining half gives error about LengthOfPageList in logs.

This gives an idea that something is broken in pega compiled version of this rule or some broken dependencies.

Any ideas will be highly appreciated.

Pega 7.1.8.

Thanks in advance,

Yuriy Berdnikov