The cover shown by the original poster (OP) is the result of Latvijas Pasts (Latvian Post) implementing new procedures as of January 1, 2020. On this date it became possible to generate postage online, consequently the procedure also changed for how to send registered mail.
Registration barcode stickers are printed in rolls and usually affixed to the shipment at the post office. Registration sticker rolls may however be given to customers sending lots of registered letters.
The cover shown in the OP's image was handed in at the post office, and the registration sticker used on the cover is of the old format - registration number and barcode only.
Standard procedure since January 1, 2020 is not to affix postage stamps to registered letters, to keep in line with online generated postage. According to official procedure, it is possible however for stamp collectors to affix postage stamps to registered letters, but this is not encouraged by staff - and most staff are very anal when it comes to procedure. In other words, in most cases it is required to identify as a "stamp collector" to create a registered cover with postage stamps affixed.
The following two images below shows a similar registered cover that was sent from Broceni, Latvia to Japan, postmarked December 14, 2020.
A curious fact about Latvian registration barcode stickers of the old format is that they are not compatible with many other postal services tracking systems when it comes to registration barcodes. Hence the added label to the registered cover with text in Japanese with the explanation that the Latvian barcode is replaced by a Japanese barcode for further procedure.
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continues after the images...)


A registered letter affixed with postage stamps and registration sticker of the new format - registration number, barcode and the text: "APMAKSATS TAXE PERÇUE". This registration sticker is compatible with at least the Swedish barcode system (most likely with other UPU-members as well).
