A Link Monster counts as either 1 material, or materials exactly equal to its Link Rating. In the second screenshot, Triple Burst is a Link 3, so it either counts as 3 materials, or as 1. Since Borrelsword needs 3+ monsters then 3+1+1=5 (hence Borrelend can be Summoned) or 1+1+1=3. In neither case did you reach 4.