diff --git a/lib/common.sh b/lib/common.sh
index 219d35b..acfa991 100644
--- a/lib/common.sh
+++ b/lib/common.sh
@@ -143,19 +143,25 @@ ui_quiet_run() {
         cur=$(sed -n "$((before+1)),\$p" "$log" 2>/dev/null \
                 | grep -E '^(Installing|Upgrading|Downgrading|Removing|Verifying|Preparing|Cleanup):' \
                 | tail -n 1 || true)
+        # Compose ONCE, then clamp to the terminal width: a live line longer
+        # than the screen wraps on every redraw and floods the screen with
+        # duplicate partial lines (VM-proven on the 80-col TTY).
+        local cols line
+        cols=$(tput cols 2>/dev/null)
+        [[ "$cols" =~ ^[0-9]+$ ]] || cols=80
+        if [[ -n "$cur" ]]; then
+            line="$msg: $cur"
+        else
+            line="$msg"
+        fi
+        if (( ${#line} > cols - 2 )); then
+            line="${line:0:cols-4}.."
+        fi
         if (( depth >= 16 )); then
             local code="${bg[$(( f % ${#bg[@]} ))]}"
-            if [[ -n "$cur" ]]; then
-                printf '\r\033[%sm \033[0m %s: %s' "$code" "$msg" "$cur" >&2
-            else
-                printf '\r\033[%sm \033[0m %s' "$code" "$msg" >&2
-            fi
+            printf '\r\033[%sm \033[0m %s' "$code" "$line" >&2
         else
-            if [[ -n "$cur" ]]; then
-                printf '\r  %s %s: %s' "${ch[$(( f % ${#ch[@]} ))]}" "$msg" "$cur" >&2
-            else
-                printf '\r  %s %s' "${ch[$(( f % ${#ch[@]} ))]}" "$msg" >&2
-            fi
+            printf '\r  %s %s' "${ch[$(( f % ${#ch[@]} ))]}" "$line" >&2
         fi
         f=$(( f + 1 ))
         sleep "$tick"