At Meta, when I click on a link, I get this error:
```
[undefined] Missing property "action"
[undefined] Value null is the wrong type for property "duration" (integer expected)
```
with this section of HTML source highlighted when I click on the line-number in webconsole:
```
&&context.nodeType===9&&documentIsHTML&&Expr.relative[tokens[1].type]){context=(Expr.find["ID"](token.matches[0].replace(runescape,funescape),context)||[])[0];if(!context){return results;}else if(compiled){context=context.parentNode;}selector=selector.slice(tokens.shift().value.length);}i=matchExpr["needsContext"].test(selector)?0:tokens.length;while(i--){token=tokens[i];if(Expr.relative[(type=token.type)]){break;}if((find=Expr.find[type])){if((seed=find(token.matches[0].replace(runescape,funescape),rsibling.test(tokens[0].type)&&testContext(context.parentNode)||context))){tokens.splice(i,1);selector=seed.length&&toSelector(tokens);if(!selector){push.apply(results,seed);return results;}break;}}}}(compiled||compile(selector,match))(seed,context,!documentIsHTML,results,rsibling.test(selector)&&testContext(context.parentNode)||context);return results;};support.sortStable=expando.split("").sort(sortOrder).join("")===expando;support.detectDuplicates=!!hasDuplicate;setDocument();support.
```
and this is shown in webconsole if I use `?debug=1`
```
GET https://meta.wikimedia.org/w/api.php [HTTP/1.1 200 OK 164ms]
GET https://bits.wikimedia.org/event.gif [HTTP/1.1 204 No Content 84ms]
"[undefined] Missing property "action"" ext.eventLogging.core.js:302
<anonymous> ext.eventLogging.core.js:302
mw.trackSubscribe/<() load.php:10744
jQuery.Callbacks/fire() load.php:3119
jQuery.Callbacks/self.fireWith() load.php:3231
jQuery.Callbacks/self.fire() load.php:3238
mw.track() load.php:10721
mw.eventLog.prepare() ext.eventLogging.core.js:185
mw.eventLog.logEvent() ext.eventLogging.core.js:295
eventLogging.logEvent() ext.popups.eventlogging.js:78
mw.popups.render.closePopup() ext.popups.renderer.js:167
mw.popups.render.render() ext.popups.renderer.js:76
mw.popups.setupTriggers/<() ext.popups.core.js:155
jQuery.event.dispatch() load.php:4640
jQuery.event.add/elemData.handle() load.php:4309
"[undefined] Value null is the wrong type for property "duration" (integer expected)" ext.eventLogging.core.js:302
<anonymous> ext.eventLogging.core.js:302
mw.trackSubscribe/<() load.php:10744
jQuery.Callbacks/fire() load.php:3119
jQuery.Callbacks/self.fireWith() load.php:3231
jQuery.Callbacks/self.fire() load.php:3238
mw.track() load.php:10721
mw.eventLog.prepare() ext.eventLogging.core.js:185
mw.eventLog.logEvent() ext.eventLogging.core.js:295
eventLogging.logEvent() ext.popups.eventlogging.js:78
mw.popups.render.closePopup() ext.popups.renderer.js:167
mw.popups.render.render() ext.popups.renderer.js:76
mw.popups.setupTriggers/<() ext.popups.core.js:155
jQuery.event.dispatch() load.php:4640
jQuery.event.add/elemData.handle() load.php:4309
```