graphic report issue

i have a tk103b device with gt06 protocol with traccar version 3.14, in traccar it supports and shows RSSI value in status window but when i try to get graphic report of RSSI it show an error:

Uncaught TypeError: Cannot read property 'elements' of null
    at g.prependMatrix (charts.js:1)
    at getIndexNearPoint (charts.js:1)
    at getItemForPoint (charts.js:1)
    at getItemForPoint (charts.js:1)
    at g.handleEvent (charts.js:1)
    at F.fire (ext-all.js:22)
    at F.fire (ext-all.js:22)
    at F.publish (ext-all.js:22)
    at F.publishGestures (ext-all.js:22)
    at F.onTouchMove (ext-all.js:22)
ext-all.js:22 Uncaught TypeError: Cannot read property 'toPrecision' of null
    at Object.correctFloat (ext-all.js:22)
    at getRange (charts.js:1)
    at g.redraw (charts.js:1)
    at g.performLayout (charts.js:1)
    at g.doScheduleLayout (charts.js:1)
    at g.fireFrameCallbacks (charts.js:1)
    at g.handleFrame (charts.js:1)
    at F.invoke (ext-all.js:22)
    at F.run (ext-all.js:22)
    at ext-all.js:22

after that i tried to view speed graphic report it doesnt show anything, maybe because the last error, is it a bug?

Probably you don't have an RSSI value in every position.

ok most of the time RSSI is 100 but i dont know when is change it.. apart from that why the error affects to the next report and doesnt show any result?, if i need to see another type of report, i have to refresh browser to view speed reports again, for example if a user is trying different type of reports he could get an error and stuck the reports when he tries with different report

Do you have RSSI value in every position?

yes but most of the cases in 100 value

Please provide a route report for the selected interval.