#76 osciloscope crash

[Key-Real]

today i had a crash:

Exception: EAccessViolation (Message: 'Access violation')
$0000000000555124 AddSampleDataForVirtualChannel, line 5325 of ../../tralala-code/src/playerstatei.inc
$00000000005545EB GetOscilloscopeSampleData, line 5530 of ../../tralala-code/src/playerstatei.inc
$00000000005BA3CC drawOscilloscopes, line 442 of FlyCode/Tracker/ChannelVisualizer.implementation.inc
$00000000005BA71A drawChannelVisualizer, line 465 of FlyCode/Tracker/ChannelVisualizer.implementation.inc
$00000000005F566D draw, line 271 of FlyCode/Tracker/theTracker.pas
$0000000000407712 $main, line 722 of FlyTracker.pas

here:

const
ScopeBufSize = 126;
type
TScopeBuf = array [0..ScopeBufSize - 1] of Single;
var
Scope : array [0..3] of TScopeBuf;
procedure drawOscilloscopes;

...

procedure TTracker.drawOscilloscopes;
var
x : longint;
i : longint;
h : longint;

begin

h:= ChannelImageHeight div 2;

for i:= 0 to 3 do begin

if (curLeftChannel + i) > Module.NumberOFChannels then continue;
if not Module.ChannelsConfig[curLeftChannel + i].enabled then continue;

PlayerState.GetOscilloscopeSampleData(FramesSinceLastTick, ossHostChannel, curLeftChannel + i, osfFloat32NE, @Scope[i], ScopeBufSize, -1, osMono, ottNone);

    for x:= 0 to ScopeBufSize - 1 do begin
    PutPixel(ChannelImage[i], x, h - floor(ChannelImageHeight * Scope[i, x]), Theme_InstrumentEditor_Oscilloscope_Color);
    end;

end;

end;

can't reproduce!
first time i have an issue with this, tested 1000000 times

ideas?