Pretokeniser error?

Looks like the pretokeniser is acting weirdly. Wanted to do some mindless blinking lights, but the code fails if I save to flash.

My code:

setInterval(function() {
  LED1.pulse(1,[10, 100, 10, 200, 20]);
}, 997);

The error from the Puck:

Uncaught SyntaxError: Got function expected '{'
 at line 2 col 14 in .bootcde
setInterval(class function(){LED1.pulse(1,[10,100,10,200,20]);},997);
                         ^
> 

.bootcde downloaded from the puck via the web ide:

setInterval(class function(){LED1.pulse(1,[10,100,10,200,20]);},997);

Output from the browser's JS console when sending (so indeed there are some tokens inside the setInterval):

"\u0010print()\n\u0010setTime(1719600866.884);E.setTimeZone(2)\n\u0010require(\"Storage\").write(\".bootcde\",\"\\nsetInterval(\\xc2ª(){LED1.pulse(1,[10,100,10,200,20]);},997);\",0,58);\n\u0010load()\n\n"

The same happens with the default "new tab" code too:

// this JS
var  on = false;
setInterval(function() {
  on = !on;
  LED1.write(on);
}, 500);

Becomes this when saved to flash:

class var on=class false;
setInterval(class function(){on=!on;LED1.write(on);},500);

If I turn off the pretokeniser, it works without any problem.
If I just send it with shift-enter, that works too.

Web IDE v0.79.3
Tested with Puck 1, Espruino 2v23 and 2v22 release. And nRF52840DK, built from latest. Same result.