1- This is from sefer shmirat haguf v’hanefesh, a contemporary collection of segulos regardless of source.
2- The version recorded there does not say that it causes tzaros, it says that having the taggim is a segula for shalom bayis.
3- If this segula is true, what did Jews do for all the centuries before we started making lameds that way?
apushatayid: ????”? ?”? get the collection of three taggim with which most people are familiar because those are mentioned in the gemara. Ketav beis yosef has a number of other single taggim, or taggim without heads (sometimes called kotzim, regular taggim are supposed to look like zayin’s) on various letters. The Lamed has two kotzim on the tip and the one on the right is supposed to be larger. Many sofrim don’t bother with the right hand kotz in tefillin and mezuzos at all because of the risk of making a psul.