There's currently an issue with Minecraft Bedrock Edition. I haven't tested this in Singleplayer only in multiplayer. It freezes most of the time for a short amount of time after using Signs or Chat. These are the only two I have experienced, but there may be other blocks that can freeze the Switch that I haven't tested. Such as the: Command block, since It uses text, and which text may be the culprit of this issue.