Created Unassigned: TabContainer Javascript error after upgrading to v15.1 [27785]

After upgrading the toolkit to version 15.1, we are getting the error below on postback.

The tab container is inside an update panel.

Any idea on how to resolve the issue?

Uncaught Sys.InvalidOperationException: Sys.InvalidOperationException: Handler was not added through the Sys.UI.DomEvent.addHandler method.ScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:237 Error$createScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:387 Error$invalidOperationScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:4152 Sys$UI$DomEvent$_removeHandlerScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:4145 Sys$UI$DomEvent$removeHandlerScriptResource.axd?d=-qISl4-OkT-7X02E4Fisr-jigs4wa_wu-6dU77P8NrNfJqi1CjDI6oSH9fU152jQRTwBaX69rlN_3T…:629 Sys.Extended.UI._CommonToolkitScripts.removeHandlersScriptResource.axd?d=6Hs5cqBUbYgAJe0EA1R4L4XMd4XJ5g3ASC-MlFJ_ya0RCEKSfxWDCcNQV30B1s0aVbwGjRJ9JfK10i…:590 Sys.Extended.UI.TabPanel.disposeScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:4854 Sys$_Application$disposeElementScriptResource.axd?d=JnUc-DEDOM5KzzVKtsL1tbbjIcOQuNa5ni3K33sqWVErbjbm8fHMHeHWVztiMdtLzupO_1WPb04CPV…:1805 Sys$WebForms$PageRequestManager$_updatePanelScriptResource.axd?d=JnUc-DEDOM5KzzVKtsL1tbbjIcOQuNa5ni3K33sqWVErbjbm8fHMHeHWVztiMdtLzupO_1WPb04CPV…:1677 Sys$WebForms$PageRequestManager$_scriptIncludesLoadCompleteScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:31 (anonymous function)ScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:47 (anonymous function)ScriptResource.axd?d=JnUc-DEDOM5KzzVKtsL1tbbjIcOQuNa5ni3K33sqWVErbjbm8fHMHeHWVztiMdtLzupO_1WPb04CPV…:358 Sys$_ScriptLoader$_loadScriptsInternalScriptResource.axd?d=JnUc-DEDOM5KzzVKtsL1tbbjIcOQuNa5ni3K33sqWVErbjbm8fHMHeHWVztiMdtLzupO_1WPb04CPV…:373 Sys$_ScriptLoader$_nextSessionScriptResource.axd?d=JnUc-DEDOM5KzzVKtsL1tbbjIcOQuNa5ni3K33sqWVErbjbm8fHMHeHWVztiMdtLzupO_1WPb04CPV…:262 Sys$_ScriptLoader$loadScriptsScriptResource.axd?d=JnUc-DEDOM5KzzVKtsL1tbbjIcOQuNa5ni3K33sqWVErbjbm8fHMHeHWVztiMdtLzupO_1WPb04CPV…:1369 Sys$WebForms$PageRequestManager$_onFormSubmitCompletedScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:47 (anonymous function)ScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:3484 (anonymous function)ScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:6376 Sys$Net$WebRequest$completedScriptResource.axd?d=D9drwtSJ4hBA6O8UhT6CQtSP95KYLELHNUSVmzcISaiv4_cmPfgn4ca4e7RIOJvlwntK35tpMB2QjF…:5996 Sys$Net$XMLHttpExecutor._onReadyStateChange