Expected:
Add a ticking area with a command block

Actual:
Command Input textbox contents replaced with pound signs. Previous Output textbox contains syntax error

Steps:

• Connect to bedrock realm
• Change gamemode to creative
  "/gamemode c @s"
• Obtain a command block
  "/give @s command_block"
• Fill command input
  "tickingarea add 1616 0 1920 1647 0 1951 sheep_farm"
• Close command block window
• Right click on previous command block
• Observe Command Input text box contains pound signs
• Observe Previous Output textbox contains Syntax error