Newline Insertion Inconsistency in File Generation

Bug Description
Claude seems to think that it's adding one newline to the end of the file, but it turns into no newlines. When I ask it to try adding two newlines to the end of the file, a single newline is added. This suggests there may be a bug somewhere around this area.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 1.0.85
• Feedback ID: 95a51965-a092-4fb1-a462-7fb392fc36f0

Errors

[{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at OV (/$bunfs/root/claude:1613:1192)\n    at map (native:1:11)\n    at wQ (/$bunfs/root/claude:1613:905)\n    at renderToolResultMessage (/$bunfs/root/claude:1770:1038)\n    at _ZW (/$bunfs/root/claude:3013:1983)\n    at AE (/$bunfs/root/claude:187:19859)\n    at Ay (/$bunfs/root/claude:189:42840)\n    at Uy (/$bunfs/root/claude:189:38363)\n    at LR (/$bunfs/root/claude:189:38291)\n    at hE (/$bunfs/root/claude:189:38145)","timestamp":"2025-09-04T17:05:31.519Z"},{"error":"Error: Tool mcp__atlassian__getAccessibleAtlassianResources not found\n    at bZW (/$bunfs/root/claude:3013:4186)\n    at AE (/$bunfs/root/claude:187:19859)\n    at Ay (/$bunfs/root/claude:189:42840)\n    at Uy (/$bunfs/root/claude:189:38363)\n    at LR (/$bunfs/root/claude:189:38291)\n    at hE (/$bunfs/root/claude:189:38145)\n    at xK (/$bunfs/root/claude:189:35208)\n    at n8 (/$bunfs/root/claude:187:4842)\n    at C2 (/$bunfs/root/claude:189:32454)\n    at <anonymous> (/$bunfs/root/claude:193:1839)","timestamp":"2025-09-04T17:05:31.567Z"},{"error":"Error: Tool mcp__atlassian__createJiraIssue not found\n    at bZW (/$bunfs/root/claude:3013:4186)\n    at AE (/$bunfs/root/claude:187:19859)\n    at Ay (/$bunfs/root/claude:189:42840)\n    at Uy (/$bunfs/root/claude:189:38363)\n    at LR (/$bunfs/root/claude:189:38291)\n    at hE (/$bunfs/root/claude:189:38145)\n    at xK (/$bunfs/root/claude:189:35208)\n    at n8 (/$bunfs/root/claude:187:4842)\n    at C2 (/$bunfs/root/claude:189:32454)\n    at <anonymous> (/$bunfs/root/claude:193:1839)","timestamp":"2025-09-04T17:05:31.568Z"},{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at OV (/$bunfs/root/claude:1613:1192)\n    at map (native:1:11)\n    at wQ (/$bunfs/root/claude:1613:905)\n    at renderToolResultMessage (/$bunfs/root/claude:1770:1038)\n    at _ZW (/$bunfs/root/claude:3013:1983)\n    at AE (/$bunfs/root/claude:187:19859)\n    at Ay (/$bunfs/root/claude:189:42840)\n    at Uy (/$bunfs/root/claude:189:38363)\n    at LR (/$bunfs/root/claude:189:38291)\n    at hE (/$bunfs/root/claude:189:38145)","timestamp":"2025-09-04T17:05:43.440Z"},{"error":"Error: {\"error\":true,\"message\":\"Failed to create issue: Bad Request. {\\\"errorMessages\\\":[],\\\"errors\\\":{\\\"versions\\\":\\\"Affects versions is required.\\\",\\\"customfield_10068\\\":\\\"Originated By is required.\\\"}}\"}\n    at BKG (/$bunfs/root/claude:1728:12044)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-09-04T17:06:36.858Z"},{"error":"Error: {\"error\":true,\"message\":\"Failed to create issue: Bad Request. {\\\"errorMessages\\\":[],\\\"errors\\\":{\\\"versions\\\":\\\"Version name 'Current' is not valid\\\",\\\"customfield_10068\\\":\\\"Specify a valid 'id' or 'name' for Originated By\\\"}}\"}\n    at BKG (/$bunfs/root/claude:1728:12044)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-09-04T17:06:54.319Z"},{"error":"Error: Request was aborted.\n    at new eW (unknown:1:28)\n    at new g9 (/$bunfs/root/claude:771:1962)\n    at new eJ (/$bunfs/root/claude:771:2750)\n    at makeRequest (/$bunfs/root/claude:788:3840)\n    at processTicksAndRejections (native:7:39)","timestamp":"2025-09-04T17:06:55.758Z"},{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at OV (/$bunfs/root/claude:1613:1192)\n    at map (native:1:11)\n    at wQ (/$bunfs/root/claude:1613:905)\n    at renderToolResultMessage (/$bunfs/root/claude:1770:1038)\n    at _ZW (/$bunfs/root/claude:3013:1983)\n    at AE (/$bunfs/root/claude:187:19859)\n    at Ay (/$bunfs/root/claude:189:42840)\n    at Uy (/$bunfs/root/claude:189:38363)\n    at LR (/$bunfs/root/claude:189:38291)\n    at hE (/$bunfs/root/claude:189:38145)","timestamp":"2025-09-04T17:23:53.989Z"},{"error":"Error: Language not supported while highlighting code, falling back to markdown: \n    at OV (/$bunfs/root/claude:1613:1192)\n    at map (native:1:11)\n    at wQ (/$bunfs/root/claude:16

Note: Error logs were truncated.