Twitter sets some limitations to its widgets. Try this to avoid a strange behaviour:
1 – The widget must always be smaller then the breakpoint. If Twitter detects that it is bigger or wider than the breakpoint, it will not show the widget.
2- If the problem continues, drag a different widget to each breakpoint, i.e: If you have these breakpoints (1200px, 680px and 420px)Add the widget to 1200px and mark it as “Hide in Other Breakpoints”. Now go to 680px breakpoint in Muse and add the widget again and select “Hide in Other Breakpoints”. Do the same with the 420px breakpoint.