As @hotNipi stated these messages arrive a different times, not in same message.
You would need to join them or save them individually as they arrive.
here are 2 examples
[{"id":"d1dc9ef0f038ad9a","type":"inject","z":"b9860b4b9de8c8da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"w1","payload":"1","payloadType":"num","x":110,"y":3800,"wires":[["a6cd69d1612d319a"]]},{"id":"a6cd69d1612d319a","type":"change","z":"b9860b4b9de8c8da","name":"save w's to global","rules":[{"t":"set","p":"my_w[msg.topic]","pt":"global","to":"payload","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":370,"y":3840,"wires":[[]]},{"id":"df448fc5681839d1","type":"inject","z":"b9860b4b9de8c8da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"w2","payload":"2","payloadType":"num","x":110,"y":3840,"wires":[["a6cd69d1612d319a"]]},{"id":"17f28bbaa3c33f0a","type":"inject","z":"b9860b4b9de8c8da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"w3","payload":"3","payloadType":"num","x":110,"y":3880,"wires":[["a6cd69d1612d319a"]]},{"id":"ca627af56bb9fc0e","type":"inject","z":"b9860b4b9de8c8da","name":"retrieve w's","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":120,"y":3920,"wires":[["5f2558cf60b78b47"]]},{"id":"5f2558cf60b78b47","type":"function","z":"b9860b4b9de8c8da","name":"function 27","func":"msg = global.get(\"my_w\") || null; //retrieve w's\nglobal.set(\"my_w\", undefined); // delete w's\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":330,"y":3920,"wires":[["907de674449ab434"]]},{"id":"907de674449ab434","type":"debug","z":"b9860b4b9de8c8da","name":"debug 315","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","statusVal":"","statusType":"auto","x":590,"y":3920,"wires":[]},{"id":"255da7d0756919fb","type":"inject","z":"b9860b4b9de8c8da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"w1","payload":"1","payloadType":"num","x":110,"y":4000,"wires":[["32233a07a8b9fb33"]]},{"id":"4b0296d44c7986ef","type":"inject","z":"b9860b4b9de8c8da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"w2","payload":"2","payloadType":"num","x":110,"y":4040,"wires":[["32233a07a8b9fb33"]]},{"id":"1f6c1623587ea85d","type":"inject","z":"b9860b4b9de8c8da","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"w3","payload":"3","payloadType":"num","x":110,"y":4080,"wires":[["32233a07a8b9fb33"]]},{"id":"32233a07a8b9fb33","type":"join","z":"b9860b4b9de8c8da","name":"","mode":"custom","build":"object","property":"payload","propertyType":"msg","key":"topic","joiner":"\\n","joinerType":"str","accumulate":true,"timeout":"","count":"3","reduceRight":false,"reduceExp":"","reduceInit":"","reduceInitType":"","reduceFixup":"","x":290,"y":4040,"wires":[["f45569406ecb1fb9"]]},{"id":"f45569406ecb1fb9","type":"function","z":"b9860b4b9de8c8da","name":"function 28","func":"msg.payload = `w1 = ${msg.payload.w1}\nw2 = ${msg.payload.w2}\nw3 = ${msg.payload.w3}`\n\n\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":450,"y":4040,"wires":[["7f550b09f36a87c9"]]},{"id":"7f550b09f36a87c9","type":"debug","z":"b9860b4b9de8c8da","name":"debug 316","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":610,"y":4040,"wires":[]}]
These examples are for info, as we do not know what output you want exactly and you not know the input timings and messages.