This is caused by an industry mess with the Quicktime / MP4 standard. LR could handle the mess better, but at this point, in my opinion it's very unlikely they will make the effort. See this bug report:
In particular, see my reply two posts down in that thread. Please add your constructive opinion to the bug report, and be sure to click Like and Follow at the bottom of the first post. That will make it a little more likely that Adobe might someday prioritize a fix, and you'll be notified when the bug's status changes.
Meanwhile, your only option is to change the times with the menu command Metadata > Edit Capture Time.
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