Tradfri Binding: cannot send command (but receive data)

Hi there, for the Tradfri thing (blind) I do receive status changes for an item but cannot send the related commands. The thing does not react. System is OH 3.3.0.M4, Tradfri gateway is 1.17.44. Debug log shows:

12:46:32.084 [INFO ] [openhab.event.ItemCommandEvent ] - Item ‘Bf_RolloNord_Position’ received command DOWN
12:46:32.084 [INFO ] [openhab.event.ItemStatePredictedEvent] - Item ‘Bf_RolloNord_Position’ predicted to become DOWN
12:46:32.085 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item ‘Bf_RolloNord_Position’ changed from 68 to 100
12:46:32.087 [DEBUG] [.internal.handler.TradfriThingHandler] - Sending payload: {“15015”:[{“5536”:100}],“3”:null}
12:46:32.089 [DEBUG] [ng.tradfri.internal.TradfriCoapClient] - CoAP PUT request
uri: coaps://
payload: {“15015”:[{“5536”:100}],“3”:null}
12:46:32.092 [DEBUG] [g.tradfri.internal.TradfriCoapHandler] - CoAP response
options: null

when items are being updated (which works), the log shows:

12:48:58.417 [DEBUG] [g.tradfri.internal.TradfriCoapHandler] - CoAP response
options: {“Observe”:773, “Content-Format”:“application/json”, “Max-Age”:604800}
payload: {“9002”:1609267828,“9001”:“Rollo Falk Nord”,“9003”:65538,“9020”:1652287224,“9054”:0,“9019”:1,“15015”:[{“5536”:66.0,“9003”:0}],“3”:{“0”:“IKEA of Sweden”,“1”:“KADRILJ roller blind”,“2”:"",“3”:“2.3.088”,“6”:3,“7”:4487,“9”:98,“8”:0},“5750”:7}
12:48:58.418 [DEBUG] [.internal.handler.TradfriBlindHandler] - Updating thing for blindId 65538 to state {position: 66, firmwareVersion: 2.3.088, modelId: KADRILJ roller blind, vendor: IKEA of Sweden}
12:48:58.419 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item ‘Bf_RolloNord_Position’ changed from 100 to 66

Any ideas?

Update: restarting the gateway solved the problem.