The server will not send client new information on a block if its visual changes have to do with block entity data, if only block entity data was being changed, and if it was changed via /setblock or /fill. In particular, signs and campfires will not change text/shown items, but there may be other blocks that I haven't thought of in which it is possible to only change block entity data and expect a visual difference.

To replicate this issue, create a sign with any text. Then use F3 + I to copy that sign's exact data, make any change to the text of the sign (or anything other block entity data that has a visual change), and run the command. As far as the server is concerned, all is well, but the client never receives the new information about the sign until prompting the server to do so via either leaving and re-entering draw distance or rejoining.

Block entity data of a sign with the problem in question:

What the sign looks like, with coordinate confirmation: