I will argue here that the believers in Rome deleted the end from copies of Paul's letter because it contained sensitive information that they did not want to fall into the hands of Nero's men.
Peter Head and Douglas Campbell have here been discussing the role of Phoebe in the delivery of Romans, and they raised the issue of the complex textual history of the letter.
There is strong evidence that there was widespread use of a version of Romans that consisted basically of chapters 1-14. Also, P46 has the doxology (Rom 16:25-27) at the end of chapter 15, suggesting that there may once have been a 15 chapter version of the letter. A further oddity is that some texts lack all references to Rome (the word is missing in both 1:7 and 1:15). From what I have been able to gather, all the versions that we have can be explained as deriving from the following early versions:
1. A version consisting of 1:1-16:27 (possibly without 16:24)
2. A version consisting of 1:1-14:23 + 16:25-27
3. A version consisting of 1:1-15:33 + 16:25-27
4. A version without mention of Rome. It doesn't matter much whether this was a form of version 1, 2, or 3.
How did these 3 or 4 versions come to be? I suggest that version 1 was the original, and that the believers in Rome created the other versions during the persecution under Nero by excising sections that contained sensitive information. Tacitus describes the persecution thus:
To scotch the rumour [that the fire had taken place to order], Nero substitued as culprits, and punished with the utmost refinements of cruelty a class of men, loathed for their vices, whom the crowd styled Christians. Christus, the founder of the name, had undergone the death penalty in the reign of Tiberius, by sentence of the procurator Pontius Pilate, and the pernicious superstition was checked for a moment, only to break out once more, not merely in Judea, the home of the disease, but in the capital itself, where all things horrible or shameful in the world collect and find a vogue. First, then, those who confessed were arrested; next, on their disclosures vast numbers were convicted, not so much on the count of arson as for hatred of the human race. And derision accompanied their end: they were covered with wild beasts' skins and torn to death by dogs; or they were fasteded on crosses, and when daylight failed, were burned to serve as lamps by night. Nero had offered his gardens for the spectacle, and gave an exhibition in his Circus, mixing with the crowd in the habit of a charioteer, or mounted on his car. (Annals 15:44.2-5)
This translation is from James Dunn, who is surely right to say, "those first arrested were tortured to divulge the names of others" (Beginning from Jerusalem p57). It seems that the authorities did not have good information on who was a Christian, and they attempted to extract information from those Christians whom they arrested. This is confirmed by what Pliny tells us about a similar situation at the start of the second century:
An anonymous list was published containing the names of many. Those who denied that they are or were Christians I have dismissed, ..... This convinced me that it was all the more necessary to find out what the truth was by the torture of two female slaves who were called deaconesses.The relevance of all this is that Nero and his men would have been eager to get their hands on a text such as Romans 16, which contained a list of the names of many of the prominent Christians in Rome. Equally, the Christians would have taken measures to keep the list of names in Romans 16 from them. They may well have cut Rom 16:1-23 from a copy of the letter, leaving Rom 1:1-15:55 + 16:25-27, which is version 3 listed above.
Another protective strategy would be to remove the references to Rome. Nero's men, on discovering such a text would have less reason to suspect that the letter contained (or had originally contained) a list of Christians in Rome. This, then, explains the version 4, listed above.
There is sensitive information also in chapter 15. I argued here that Paul's collection for Jerusalem was illegal, and I showed here that, when Paul was on trial, he had to choose his words very carefully when alluding to the collection. Therefore, when Paul was facing trial in Rome, his case might have been jeopardized if Rom 15:25-27 fell into the hands of the authorities. I imagine also that Rom 15:12 could have been used against Paul by the prosecution. So, the owner of a copy of Romans might have wished to protect Paul and/or their friends by removing Rom 15:12 and/or Rom 15:25-27 and/or Rom 16:1-23. They might also have needed to remove the dangerous text in such a way that it would not be obvious that the excision had taken place (lest they be tortured for the information in the missing fragments). To hide their surgery they would have to delete more than just the dangerous text. They would need to shorten the letter to a point that sounds as though it could have been a letter ending. They may have cut off the last sheets, so 14:33 was on the final sheet. Then, having erased the text below 14:33 they may have copied out 16:25-27 just below 14:33 to make it seem like no excision had taken place. This, then, would explain version 2, listed above.
So, it seems to me that the puzzling variations in the texts of Romans can be simply explained by the persecution under Nero. I am no expert in textual criticism and would be happy to know if I have missed something.