BP 1.2.6 made some changes to the way buttons are rendered.
Read this for more info:
https://codex.buddypress.org/extending-buddypress/bp-default-theme-changelog/
Follow the steps listed in the second point.
If you encounter any other problems with your child theme, please post follow-up responses in this thread.
@r-a-y thanks for the reply.
I haven’t edited any of the theme files listed in point two. Could it be css changes I’ve made?
Thanks
Anyone have any ideas on this?
You may not have edited the files, but were they copied into your child theme?
No, I don’t think so. These are the only files I have in the child theme:
– _inc/images/whateverimages…
– child-functions.php
– footer.php
– header.php
– index.php
– sidebar.php
– single.php
– style.css
Can you try overwriting what is in your /buddypress/bp-themes/bp-default/ folder from the manual package?
Do the buttons show up when you use the bp-default theme?
No problem! So does that mean you fixed your problem? 
Yeah just re-uploaded the latest version of bp-default 
