Short answer: It is said in some old notes that one stanza (gātha) of the Uvasaggaharam Stotra was abolished long ago, but there is no universally fixed record of exactly which stanza that was. Over time the text has varied, and different lineages report different versions. Today most widely circulated texts present a 4–5 stanza form, and the claim of a single permanently removed stanza does not have a single agreed-upon identification. This topic is tied to historical changes in the text and to differences between Śvetāmbara and Digambara references. ( jainphilosophy.blogspot.com, jaincosmos.blogspot.com, en.wikipedia.org)

• In Śvetāmbara tradition, Uvasaggaharam Stotra is one of the Nav Smaran and is often presented with five stanzas in many modern editions, while older recensions are said to have had more, with some stanzas later reduced. The idea of a single “removed” stanza appears in some secondary discussions, but there is no universally agreed which one it was. ( jaintreasures.org.uk, jainuniversity.org)
• Some sources note that the original form had many more verses and that a number were dropped over time; exact identification of the dropped stanza is not fixed in authoritative Jain scriptures. ( en.wikipedia.org)

If you want, I can point you to specific Śvetāmbara or Digambara text editions and their stanza counts. Here are references you can consult:

• Uvasaggaharam Stotra overview and texts:
• Uvasaggaharam Stotra (general text and notes):
• Uvasaggaharam Sutra overview:
• Wikipedia summary (historical notes on stanza counts):

Note: If you want, I can give you the exact text of the currently accepted verses from a specific tradition (Śvetāmbara or Digambara) and explain their meanings.