Hi @luther.mallari. I know how much you love a conversation on messenger with an emoji. I could say that it's messenger's bug causing you the issue. But then, let me first suggest some options in order for us to arrive in identifying the caused issue.
First, do check on the version of the Messenger that you downloaded.
1. Tap to open Settings 2. Look for Apps and tap on it 3. Look for the messenger and tap on it.
Right below the icon of the Messenger you will see the version. I have my messenger downloaded an hour ago and the version is : 184.108.40.206.64
The purpose of having that thumbs up emoji (actually not just that, there are more for you to choose from) is there a your default emoji during your conversation instead of tapping on the "four circles" icon to open the emoji selection. Try to change that thumbs up emoji into a different one.
1. Open a conversation on your messenger. It doesn't matter if active or inactive conversation. On the right side top you can see 3 icons of video, phone/call, and i inside the circle. Tap on i.
2. Tap on the emoji, half screen will show the selections of the emoji. Select 1 and that will appear below the messenger's conversation box next to write a message.
Now, if the problem persists, have it reported to Facebook,
1. Go to the conversation box and tap the i. You will see <------ Details and on the right side there are 3 small vertical circles.
2. Tap that vertical circles and select Report a Problem.
3. Fill in the given space with your report (e.g. The default emoji I wanted to use on my messenger's conversation is not working. It does not appear on the conversation once I tapped to use it.)
4. Tap on SEND just right above your written report.
I hope that these given options will help you out to resolve the issue. Should you need further assistance please don't hesitate to drop us a line. Thank you.