Looking at some eventlogging logs, I see occasional invalid events for the Popups schema. It looks like the totalInteractionTime field is sometimes set to `null`, but it is required to be an integer.
```
2017-11-13 15:26:32,297 [8480] (MainThread) Unable to validate: ?%7B%22event%22%3A%7B%22pageTitleSource%22%3A%22South%20Korea%20in%20the%20Vietnam%20War%22%2C%22namespaceIdSource%22%3A0%2C%22pageIdSource%22%3A40906410%2C%22isAnon%22%3Atrue%2C%22popupEnabled%22%3Atrue%2C%22pageToken%22%3A%2275877e98a26f57c1%22%2C%22sessionToken%22%3A%22d855c363bf2ceb19%22%2C%22hovercardsSuppressedByGadget%22%3Afalse%2C%22previewCountBucket%22%3A%221-4%20previews%22%2C%22totalInteractionTime%22%3Anull%2C%22action%22%3A%22dismissed%22%2C%22linkInteractionToken%22%3A%22106b1f8f3420bbb1%22%2C%22pageTitleHover%22%3A%22White_Horse_Division%22%2C%22namespaceIdHover%22%3A0%2C%22previewType%22%3A%22page%22%2C%22perceivedWait%22%3A834%7D%2C%22revision%22%3A16364296%2C%22schema%22%3A%22Popups%22%2C%22webHost%22%3A%22en.wikipedia.org%22%2C%22wiki%22%3A%22enwiki%22%7D; cp4027.ulsfo.wmnet 2682473 2017-11-13T15:26:31 - "XXXXXXXX" (None is not of type 'integer')
```
####Developer notes
Decoded event data:
```
{
"event":
{
"pageTitleSource":"South Korea in the Vietnam War",
"namespaceIdSource":0,"
pageIdSource":40906410,
"isAnon":true,
"popupEnabled":true,
"pageToken":"75877e98a26f57c1",
"sessionToken":"d855c363bf2ceb19",
"hovercardsSuppressedByGadget":false,
"previewCountBucket":"1-4 previews",
"totalInteractionTime":null,
"action":"dismissed"
,"linkInteractionToken":"106b1f8f3420bbb1",
"pageTitleHover":"White_Horse_Division",
"namespaceIdHover":0,
"previewType":"page",
"perceivedWait":834
},
"revision":16364296,
"schema":"Popups"
,"webHost":"en.wikipedia.org",
"wiki":"enwiki"
}
```