Solved

Daily Rewards 40 XP

What did you try to do?
Checked the XP required to next level was sitting at 1093
Selected the bonus under the 40 XP day.
It showed 20 XP
Expecting 60 XP to be added

What happened instead?
Only 20 XP was added as the XP required to next level changed to 1073 instead of 1033

Did the problem happen while using wi-fi, mobile data, or both?
Wi-fi

Did the bug happen in the app, on PC, or both?
PC

What operating system is your PC?
Mac OS

Which browser did you experience the problem in?
Chrome

Can the bug be reproduced?
On the Daily bonus day 4, one of the extra bonus may give XP

Additional comments:

Sorry to use this thread but it it is the same issue. 
I thought I experienced the same a few times but wasn't 100% sure and brushed it off. I have a habit of always checking exp before I grab my daily and noticed it yesterday on this account I think. Logging in and out didn't help. All incidents have been in the last 2-3 days on my different accounts. Using chrome on PC and app on android tablet and phone.

I have also experienced this issue

Ok now it happened on this account too. I got 40xp+20xp But only gained 20xp 2003 > 1983

I had the same issue.

How many accounts do you have?

This is a bit off topic but I play 4 accounts actively.

Now it again happened on my main account. Slightly different this time. Day three reward was one engine, the extra/bonus reward I got said 20xp but I only received 10 xp, 3228 -> 3218

This just happened to me today again.

This happened again.... when will it be fixed?

Reported to the developer team. I’ll keep the topic open to report updates on this problem/bug. 

This is still an issue, and now that main daily deals have changed to include two days with XP it can happen even more.

Thanks