gta3 Implying it is a GOS issue.
I think you may be misunderstanding what's being said and how the project works.
The default keyboard is not developed or maintained by the Graphene project; instead they ship an existing keyboard, I believe the AOSP standard. The issue can occur on devices using this keyboard regardless of if it is running Graphene or not.
Since it is not their code they are not going to fix it. They will eventually 'fix' the situation by including a different keyboard as the default when there's one that they deem an adequate replacement, but will not be writing any code for the current or future one.
If you are desperate to avoid replacing the keyboard yourself and willing to give money to have it fixed, you would be better served making an offer to the developers of the current keyboard or to developers of FlorisBoard, the likely replacement once that team finishes a few more features.