Sforno on Genesis 38:5/ספורנו על בראשית ל״ח:ה׳

1והיה בכזיב, the reason why she called their third son Shelah, a word reminiscent of Kings II 4,28 (לא) תשלה, “(do not) deceive, disappoint, disillusion,” a name which is not exactly complimentary to the bearer of it, was due to Yehudah being in כזיב, i.e. a reference to his being absent, so that she did not have this moral support when she began the labour pains prior to giving birth to her third son. [I am not sure if the author understood the Torah as using to the word כזיב to describe Yehudah’s state of mind, and that there was no such place at all. Ed.] Had he been there, he would never have agreed to the name she gave his son.