'A non-proceed event occurred while processing the request: Yes' when attempting SLO

[Zacharyzachary Pearson]

I am attempting to log the user out using <idp-server>/idp/profile/Logout, but when it asks for verification (it gives me the choice between ‘yes’ and ‘no’) and I click yes an error page shows up saying ‘An error occurred: Yes’. However, if I allow the few seconds to expire where it will automatically log me out, it does not give an error like this. Looking at the IdP-Process.log, logging level set to Trace, I see the following during the relevant time period:

2018-02-16 16:42:56,291 - INFO [Shibboleth-Audit.Logout:275] - 20180216T224256Z||||http://shibboleth.net/ns/profiles/logout||||admin|||||
2018-02-16 16:42:56,294 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'en'
2018-02-16 16:42:56,294 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'en'
2018-02-16 16:42:56,294 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'fr'
2018-02-16 16:42:56,295 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'de'
2018-02-16 16:42:56,295 - DEBUG [net.shibboleth.idp.ui.context.RelyingPartyUIContext:363] - Not a usual scheme, returning name of '10.113.80.109'
2018-02-16 16:42:56,295 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'en'
2018-02-16 16:42:56,295 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'en'
2018-02-16 16:42:56,295 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'fr'
2018-02-16 16:42:56,295 - TRACE [net.shibboleth.idp.ui.context.RelyingPartyUIContext:315] - No name in UIINFO for 'de'
2018-02-16 16:42:56,296 - DEBUG [net.shibboleth.idp.ui.context.RelyingPartyUIContext:363] - Not a usual scheme, returning name of '10.113.80.109'
2018-02-16 16:42:59,132 - TRACE [net.shibboleth.idp.profile.support.ProfileRequestContextFlowExecutionListener:62] - Updating ProfileRequestContext in servlet request
2018-02-16 16:42:59,141 - WARN [org.opensaml.profile.action.impl.LogEvent:105] - A non-proceed event occurred while processing the request: Yes



The only difference between the successful and non-successful logouts are the very last line "WARN [org.opensaml.profile.action.impl.LogEvent:105] - A non-proceed event occurred while processing the request: Yes”.

I am having to test this on IE11 as per company specs, does not have issues on chrome