Chrome Version: 63.0.3223.7
OS: Android O, Nexus 6P

What steps will reproduce the problem?
(1) Install twitter light WebAPK
(2) Wait for a notification
(3) Click on the notification

What is the expected result?
Expect to see some UI (even if just a splash screen) within a second or so.

What happens instead?
Can wait for 10 seconds or more with no UI update. Is something blocking on the network or some timeout?

I showed Yaron this happen today and he was shocked, so perhaps it's my device somehow.  Do we have the ability to gather metrics on the latency?  I'll try to grab a trace when I get a chance, but it would be helpful to know if this reproduces for others.