I believe that there is a typo in the summon construct spell from Tasha's Cauldron of Everything. The spell is shown as a 4th-level spell in the table at the beginning of the chapter (p. 105) and in the main entry for the summon construct spell (p. 111).
However, the Construct Spirit's stat block lists its HP formula as:
"40 + 15 for each spell level above 3rd" (emphasis mine).
This is odd, because all of the other stat block formulas for all the other summon [X] spells in the book are formatted such that you only add extra HP if the spell is cast at a higher level.
By RAW, based on the given formula, the construct has 55 HP when cast as a 4th-level spell. However, have there been any designer statements or errata indicating that this was unintentional and that the base HP should actually be 40?