Application Version (from "Chrome Settings > About Chrome"): 51.0.2704.81
Android Build Number (from "Android Settings > About Phone/Tablet"): MPB24.65-34, LPBS23.13-56-2
Device: motorola and Xiaomi android phones

Steps to reproduce: 



Observed behavior: 

mayLaunchUrl not working for some of the android devices with latest chrome i.e. 51.0.2704.81. but after uninstalling and reinstalling the chrome it started working as expected. I checked with your demo app for chrome custom tabs and with my application also. I checked it with 10 devices out of which 5 of them showing this unexpected behaviour

Expected behavior: 

As described in documentation https://developer.chrome.com/multidevice/android/customtabs, on calling the warmup and mayLaunchUrl methods, initial connection to the server and pre-fetching of the content should happen
 
Frequency: 
<number of times you were able to reproduce> 

every time I tried on those specific devices before uninstalling and reinstalling the chrome. 


Additional comments: 

I was able to observe the expected behaviour after uninstalling and reinstalling chrome.