Thank you for making this report. The behavior you've described is how the Time-Reverse Keyframes function is currently designed: it reverses all the keyframes within any selected keyframes, not only the selected keyframes. To have it work as you've described would be considered a feature request rather than a bug report.
Let me know if I should move this report to our Ideas section for further conversation and votes.
I'm not sure this is a bug, it just seems that this is the function of the time reverse keyframes command.
Any keyframes between the selected keyframes have to be affected by the command.
Think of a position animation, if you could only time reverse selected keyframes (let say the first and last) it would change the structure of the entire animation. Though non-linear time reversal would probably be interesting for some properties.
Thank you for making this report. The behavior you've described is how the Time-Reverse Keyframes function is currently designed: it reverses all the keyframes within any selected keyframes, not only the selected keyframes. To have it work as you've described would be considered a feature request rather than a bug report.
Let me know if I should move this report to our Ideas section for further conversation and votes.