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### Description Kamailio seems to fail to properly route in-dialog SUBSCRIBE with the topos module enabled. In this configuration, SUBSCRIBEs are expected to be delivered to a downstream UAS, an asterisk instance in the internal network.

record_route() is executed for all initial requests, including SUBSCRIBEs. Routing is performed correctly with the topos module disabled, no other modifications were needed. <!-- Explain what you did, what you expected to happen, and what actually happened. -->

### Troubleshooting I haven't been able to work around this issue in any other way other than disabling the topos module. #### Reproduction The configuration used is a heavily modified version of the example configuration file, but the handling of SUBSCRIBEs is generally simple. The initial SUBSCRIBE is subject to some tests, the R-URI is edited and dispatched to a farm of asterisk servers based on some criteria. Record Routing is enforced, so subsequent in-dialog re-SUBSCRIBEs are expected to be routed with loose_route(), which doesn't seem to handle things properly. <!-- If the issue can be reproduced, describe how it can be done. -->

#### Debugging Data I'm attaching kamailio logs with debug=4, cfg_trace <!-- If you got a core dump, use gdb to extract troubleshooting data - full backtrace, local variables and the list of the code at the issue location.

gdb /path/to/kamailio /path/to/corefile bt full info locals list

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#### Log Messages See attachments <!-- Check the syslog file and if there are relevant log messages printed by Kamailio, add them next, or attach to issue, or provide a link to download them (e.g., to a pastebin site). -->

#### SIP Traffic Please see: https://www.cloudshark.org/captures/d2643aae7f2a <!-- If the issue is exposed by processing specific SIP messages, grab them with ngrep or save in a pcap file, then add them next, or attach to issue, or provide a link to download them (e.g., to a pastebin site). -->

### Possible Solutions

Using topoh instead for topos, but unfortunately this will break communication for other reasons (messages too large/UDP fragmentation for some peers).

### Additional Information * **Kamailio Version** Tried with kamailio 5.1.6 and kamailio 5.3.0-dev0 deb.kamailio.org repositories were used to acquire binaries for both versions

* **Operating System**: Debian Stretch <!-- Details about the operating system, the type: Linux (e.g.,: Debian 8.4, Ubuntu 16.04, CentOS 7.1, ...), MacOS, xBSD, Solaris, ...; Kernel details (output of `uname -a`) --> [resubscribe.log](https://github.com/kamailio/kamailio/files/2586440/resubscribe.log)