Curious event behaviour

Hello out there,
take the following script:
---
package require Tk
foreach ch [winfo children "."] {destroy $ch}

# This variable controls whether the events happen during the script's
# execution or are scheduled for some time after
set evInScript 0

set c [canvas .c -width 400 -height 300 -bd 0 -bg lightyellow]
pack $c
set id1 [$c create rectangle 100 100 200 200 -fill red]
set id2 [$c create rectangle 200 100 300 200 -fill green]

foreach id [list $id1 $id2] {
    $c bind $id <Button-1> [list puts "<Button-1> for id $id"]
    $c bind $id <Shift-Button-1> [list puts "<Shift-Button-1> for id
$id"]
}
if {$evInScript} {
    after 1000
    event generate $c <Button-1> -x 150 -y 150
    after 2000
    event generate $c <Shift-Button-1> -x 250 -y 150
} else {
    after 1000 {event generate $c <Button-1> -x 150 -y 150}
    after 2000 {event generate $c <Shift-Button-1> -x 250 -y 150}
}
puts "Done for evInScript == $evInScript"
---
It programs two events which are to be executed either "inline" in the
script (evInScript == 1) or scheduled for some time after.
This is the result:
---
Microsoft Windows [Version 10.0.19045.4842]
(c) Microsoft Corporation. Alle Rechte vorbehalten.

d:\proj\_ToolsSE\Skeleton\TclTests>tclsh tst.tcl
Done for evInScript == 0
<Button-1> for id 1
<Shift-Button-1> for id 2

d:\proj\_ToolsSE\Skeleton\TclTests>tclsh tst.tcl
Done for evInScript == 1
---
In the second case the events never happened (or they happened but
were not recognized, which amounts to the same). I consider this a
bug. Should I submit a ticket?

This is on Windows 10 with Tcl 8.6.10 and 8.6.13
Helmut