Bad notification exception only under Android 6.0.1

On my latest beta I've started receiving a crash on Crashlytics that says android.app.RemoteServiceException: Bad notification posted from package but it is only happening for Android 6.0.1 and only on some phones. I haven't been able to reproduce it myself yet.

If I do a diff of all files involved between the first version it showed up at and the last one where it didn't, the only changes I see are updates to libraries, particularly it seems like I went from support library 27 to 28. I don't have any changes to how I create my notifications.

Anyone have any idea what might be going on? How can I figure out which remote view might be causing the issue? I've had these notifications for a really long time without this issue.

Fatal Exception: android.app.RemoteServiceException: Bad notification posted from package mypackage: Couldn't expand RemoteViews for: StatusBarNotification(pkg=mypackage user=UserHandle{0} id=74219 tag=null score=-10 key=0|mypackage|74219|null|10157: Notification(pri=-1 contentView=mypackage/0x7f0c00dd vibrate=null sound=null defaults=0x0 flags=0x62 color=0x00000000 vis=PUBLIC))
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1526)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:148)
       at android.app.ActivityThread.main(ActivityThread.java:5461)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)