Debugging in gdb is broken

When I try debugging a running process (i.e. Debug -> Start Debugging -> Attach to Running Application...), QtCreator is unable to associate breakpoints in the source code with the executable. Basically, this renders breakpoints unusable.

In the Breakpoints view at the bottom, the panel lists my breakpoints and, while the process is suspended, the "Number" column for each breakpoint is continuously incremented over time. If I hover over the breakpoint icon in the source code editor, the tooltip that appears shows a snapshot of the ever-increasing number as the Internal ID of the breakpoint (i.e. every time you invoke the tooltip the ID is updated with a new value).

Also if I press F5 in the debug mode while the debugged process is suspended, QtCreator tries to compile and run the project instead of continuing execution of the suspended process. The F5 key (with no modifiers) is bound to "Start Debugging or Continue" and nothing else in the settings. Apparently, "Continue" doesn't work.

These problems were not present in QtCreator 4.7.1.